I decided to continue writing my review for this book here once I found out that my review was hitting the character limit in goodreads. I started writing this review immediately after reading the first two stories of this book since I felt sure by then that this book would be a masterpiece. This book has a collection of hard sci-fi short stories, which means you don't have to read it all at once, you can pace yourself one story at a time. It has been a while since I had to slow down and reread paragraphs to really understand the complex world that was being created. Some minor spoilers follow so I recommend that you first read the story before reading the relevant review.

The Infinite Assassin - 4/5

There was one thing that did not make sense to me, I don't think the author was clear enough ton how/why simulator trips were absurd and empty. I think you'd have a high degree of freedom to make it as realistic as you'd wish. So the S dreams should have been a bit more motivated. Still the story had this idea of flow which was so beautiful,

The trouble is, there’s never anything so simple as an infinity of direct exchanges, between all the versions of the mutant user who’ve gained this power, and all the versions they wish to become. Such transitions are energetically unfavourable; in practice, each dreamer must move gradually, continuously, passing through all the intervening points. But those ‘points’ are occupied by other versions of themselves; it’s like motion in a crowd — or a fluid. The dreamers must flow.
At first, those alter egos who’ve developed the skill are distributed too sparsely to have any effect at all. Later, it seems there’s a kind of paralysis through symmetry; all potential flows are equally possible, including each one’s exact opposite. Everything just cancels out.
The first few times the symmetry is broken, there’s usually nothing but a brief shudder, a momentary slippage, an almost imperceptible world-quake. The detectors record these events, but are still too insensitive to localise them.
Eventually, some kind of critical threshold is crossed. Complex, sustained flows develop: vast, tangled currents with the kind of pathological topologies that only an infinite-dimensional space can contain. Such flows are viscous; nearby points are dragged along. That’s what creates the whirlpool; the closer you are to the mutant dreamer, the faster you’re carried from world to world.


To really appreciate the end of this story you need to know a bit of measure theory (real analysis) and what a cantor set is. Overall it was a short good read. Above average for sure.


The Hundred-Light-Year Diary - 5/5

This is the story which motivated me to come here and write both reviews. I've been struggling for the past few years to come to terms with the idealistic definition of free will that is accepted in most cultures. This story takes the problem head on. I struggle to convince friends but actually this below paragraph is all that we need, to show how causality contradicts the Libertarian ideal of free will.

Ascribing motives is a strange business, but I’m sure it always has been. Knowing the future doesn’t mean we’ve been subtracted out of the equations that shape it. Some philosophers still ramble on about ‘the loss of free will’ (I suppose they can’t help themselves), but I’ve never been able to find a meaningful definition of what they think this magical thing ever was. The future has always been determined. What else could affect human actions, other than each individual’s — unique and complex — inheritance and past experience? Who we are decides what we do — and what greater ‘freedom’ could anyone demand? If ‘choice’ wasn’t grounded absolutely in cause and effect, what would decide its outcome? Meaningless random glitches from quantum noise in the brain? (A popular theory — before quantum indeterminism was shown to be nothing but an artefact of the old time-asymmetric world-view.) Or some mystical invention called the soul . . . but then what, precisely, would govern its behaviour? Laws of metaphysics every bit as problematical as those of neurophysiology.
I believe we’ve lost nothing; rather, we’ve gained the only freedom we ever lacked: who we are is now shaped by the future, as well as the past. Our lives resonate like plucked strings, standing waves formed by the collision of information flowing back and forth in time.

But while this was the main reason for loving this story, the story has other stuff to offer too. The time reversal idea that involved "sensors" that emitted photons that were meant to be absorbed reminded me of the actual absorber theory created by Feynman. As the wiki page explains - "advanced waves could be detected before their emission". It is worth thinking about these things that we implicitly take for granted to be true like causality.

These are the kind of stories that I hope will become more commonly written, one for every exotic math concept or philosophy concept. Storytelling is the best, most beautiful way to illustrate these ideas.

Eugene - 3/5

The idea was very well developed. The inital idea itself is great and shows the farsightedness of the author. Genetic engineering will inevitably be culturally embraced and initially be accessible to the super rich. But I did not find the Nirvana goal to make sense. I understand it's a short story so something like this could only be done. I wish it was longer or I could see some deeper meaning in why It would want Nirvana.

Caress - 3/5

It was definitely a novel idea. That kind of madness that is plausible and even possible in the far future. It was not that well written, I found it was kind of rushed and the idea was too expansive to fit into such a short story.

Blood Sisters - 3/5

The idea of double blinded trials, how individual dignity and life might have to be sacrificed for the sake of the greater good, to generate data we can trust. Increasingly to make breakthroughs in biology we will hit against such moral barriers. I wonder what direction we will pick. The story itself was not compelling and I was unable to see how many of the threads connected.

Axiomatic - 4.5/5

Maybe I expected too much since the collection was named after this story. But it was really good. Almost 5. Have you ever wondered how someone could possibly believe that human life was not sacred? Say they support the death penalty. Did they read the research on how it is not a deterrent? Did they think deeply on it before deciding it's ok to kill humans for these reasons. This is more general than just this issue. Maybe you don't think my point above is obvious, choose some other belief you think is obvious. How do people accept a belief that seems to you unsupported by evidence? I think this quote from the book perfectly captures how the idea remains elusive for them, they can't make sense of it.

I asked myself, out loud, ‘Is human life sacred? Is it wrong to kill?’ but I couldn’t concentrate on the question, and I found it hard to believe that I ever had in the past; the whole idea seemed obscure and difficult, like some esoteric mathematical theorem. The prospect of going ahead with my plans made my stomach churn, but that was simple fear, not moral outrage;



This had other gems too, like how tiring it can be to keep all the contradictory voices alive inside you. How comforting certainty can be. How you wish you could do or have something but your conscience acts as a shackle.

Being true to myself would have meant living with all my contradictory urges, suffering the multitude of voices in my head, accepting confusion and doubt. It’s too late for that now; having tasted the freedom of certainty, I find I can’t live without it.

The Safe-Deposit Box - 5/5

I am a sucker for any story that touches on consciousnesses. There is a lot of fascinating research on how powerful our neuroplasticity is. Especially the younger we are, the more we can compensate for such damage. Consciousness does seem to be a hardy thing. Trying to survive much like a physical organism. I think The Fifth Science might be a good book for you to try if you enjoyed this particular story a lot.

One of the deep quotes from this story touches on the fact that we form a representation in our minds for our lover, a coarse one, a crude approximation formed from "unifying patterns" derived from our memories, such that they are instinctual. This is best understood by seeing how this "being" is also able to love and conceptualize a wife on this same level. It's hard for us to do that since we do not have access to the memories he has, nor are we in that state of mind where we can accept that thing as a coherent entity. We have stricter standards for what it means to be such an entity. But it's a crazy mindblowing insight that it is possible to love such a composite woman.

Not only is it untrue, it simply doesn’t matter. Yes, my lover has a thousand faces, and yes, a different soul looks out from every pair of eyes, but I can still find (or imagine) as many unifying patterns in my memories of her, as any other man or woman can find (or imagine) in their own perceptions of their own most faithful lifelong companion

Seeing - 3/5

An interesting idea, but I don't see the larger purpose of this idea. I guess we do take it for granted the first person view we all have. The third person view or many person view might be common in the future. One great point they raised in this story is the common misconception people have that vision is merely like a camera, picking up light from our surrounding. Our eyes are like cameras, sure. But human vision is so much more cooler. We don't "see" a picture. We experience the world, we merge all the senses, make use of priors to make sense of what we see, fill in gaps, ignore stuff, lots of background processes are constantly working, monitoring peripheral vision for movement etc.

‘Forget about cameras. Vision is nothing like photography — it’s an elaborate cognitive act. A pattern of light on your retina doesn’t mean a thing until it’s been analysed: that means everything from detecting edges, detecting motion, extracting features from noise, simplifying, extrapolating — all the way up to constructing hypothetical objects, testing them against reality, comparing them to memories and expectations . . . the end product is not a movie in your head, it’s a set of conclusions about the world.

‘The brain assembles those conclusions into models of your surroundings. The primary model includes information about more or less everything that’s directly visible at any given moment — and nothing else. It makes the most efficient use of all your visual data, and it makes the least possible number of assumptions. So it has a lot of advantages — but it doesn’t arise automatically just because the data was gathered through your eyes. And it’s not the only possibility: we all build other models, all the time; most people can imagine their surroundings from almost any angle—’

A Kidnapping - 5/5

Scanning our brain should be possible... eventually I think. Maybe our physical brain can't survive the process but this idea is not far fetched at all! with rat brain tissue recently being mapped at the synaptic level. Anyway even if it can be done, people may not be convinced that consciousness can exist in things other than biological matter. We tend to think of our identity as being intrinsically bound with our physical body. But as far as we understand the human body, every single atom in our body is replaced within maybe 5 years. So we are not the physical body, we are the pattern spelled out in this medium. This brings to mind that thought experiment about the Ship of Theseus. Anyway this is a popular idea used by sci fi authors, what made this story special is that he took it further. He explained how we can only love someone insofar as we know that someone. We can't love our wife, we can only love the representation of her in our brain. Now while I don't agree (upscaling from a low dimensional representation like that?!) that you can create a person out of that crude representation, you should be able to create a thing that can fool your instinct, always avoid surprising you, maybe we can even slowly let that thing grow and learn and become a person. I think the idea itself is worth knowing.

Learning To be Me - 3/5

I've been convinced the organic brain is nothing special for quite sometime now. So this story did not really push me. The best stories challenge your worldview. This story was quite interesting and sadly I could see something like this happening. Now the one idea this story made me think deeply was how our conscious mind seems to make up reasons for any action our unconscious mind decides to do. Intention is quite delusional (this is better discussed in the Vat story). But if you had managed to become free and choose to will something else, then you would be an observer in your body, forced to watch yourself take actions.

This also made me think about the split brain experiments that were conducted which shows how we easily explain away and even fool ourselves regarding WHY we do something.

A patient with split brain is shown a picture of a chicken foot and a snowy field in separate visual fields and asked to choose from a list of words the best association with the pictures. The patient would choose a chicken to associate with the chicken foot and a shovel to associate with the snow; however, when asked to reason why the patient chose the shovel, the response would relate to the chicken (e.g. "the shovel is for cleaning out the chicken coop")

The Vat - 4/5

I wish it was longer, I wish I could have heard from her view. Just like Harold, I think it's crazy to imagine the brain one day understanding itself. That sort of self reference is beautifully paradoxical but within the reductionist philosophy it seems possible.

Above all, he dizzily marvels at the fact that the molecules in his brain have managed, collectively, to understand themselves: his neurotransmitters are part of a system that knows what a neurotransmitter is. He can sketch the structures of the central nervous system’s one hundred most important substances; he’s synthesised half of them with his own hands. He’s even viewed real-time images of his brain metabolising radioactively-labelled glucose, revealing which regions were most active as he watched himself thinking about watching himself think.


The main idea which I loved in this story is about how the belief in free will in most people can sustain itself because of how strongly axiomatic that belief is. The people like me and Harold who dismiss it are just switching it out for a different axiom! we are holding the idea of Logical Thought to be equally axiomatic. But that is fine because the objective is to hold the least number of independent axioms and still function well.

All people involved can be shown the same facts and yet will infer differently based on the values they hold most dear. Finally the beauty is in how well you can hold onto logical thought so obsessively that you can undermine yourself. You can sit in comfort and luxury made possible by some "ism" and denounce it even though it was what enabled you and gave you the time and space required to reach that conclusion. This does not make the conclusion automatically without merit, but it is ironic.

The neurological facts refuse to stay decently theoretical; the irony is that this shattering of the illusion of will, although entirely reasonable, is not by any means necessary; after all, the human brain is under no deep biochemical edict to be reasonable. The epiphenomenon of logical thought simply happens to have been more resilient, in this case, than the epiphenomenon of will; in a million other people, as familiar with the facts as Harold, the battle happens to have gone the other way.

Harold wonders, with a mixture of unease and fascination, if his reason is strong enough to move on from this conquest to the ultimate triumph of undermining itself.

The Walk - 4/5

Again I accept that the continuity of identity across a human's lifespan is just a useful myth. Most of us don't have eidetic memory and anything that really characterizes us would not be so complicated that it fully required the complete DNA and all memories to reconstruct. I would guess "we" (the conscious self aware part) are far simpler than that. But the space of all possible identities is too high dimensional for there to be another me, statistics can't help because the environment will change, culture will change. It's not even a random walk in this space, not that it would help. Even if it was probable, it would only be for a few seconds. But as an ideal, as an abstract platonic idea. I would be immortal by definition.

It’s seeing the life of your body as the life of one person that’s the illusion. The idea that “you” are made up of all the events since your birth is nothing but a useful fiction. That’s not a person: it’s a composite, a mosaic.’

But this story also offered something new to me - that there was one more idea about how best to look at time, analogous to space. If I want to occupy all of space, to be omniscient in that sense. That is the sort of immortality applied to time. It was a nice example, showing how funny it can be to an alien - the wish to live for as long as possible. Pointing to how the Will to survive is a biological imperative. It actually does not make any sense because we die many times in our lifetime.

Look at it this way: Does it bother you that there are places outside your skin — and you’re not in them? That you come to a sudden end at the top of your skull — and then there’s nothing but air? Of course not. So why should it bother you that there’ll be times when you won’t be around — any more than you care that there are places you don’t occupy? You think your life is going to be undone — cancelled out, somehow — just because it has an end? Does the space above your head cancel out your body? Everything has boundaries. Nothing stretches on forever — in any direction.’

A story that kind of, tangentially covered my point is the Mother of Learning by nobody103. I highly recommend you read it. Major spoilers for the book follow, come back here after you finish reading. It is a page turner.

You Have Been Warned

So you can see how the characters in the book react to being told they are stuck in a time loop. All of them are understandably distressed but they did not really see it as a "True Death". They knew "they" would live on, not the exact them but someone who was close enough that they did not mind that much. So this shows how death is not really discrete. The longer the duration of the time loop, the more closer to a true death they would have to face. This is why Zach and Zorian wanted so badly to go back to the real world. For them it felt like a true death. So my point is that its not too far fetched to consider a society that did not think teleportation was murder. It all depends on how you define what you are.

Further applying this to our current reality, consider what you are. Over time that will change. You don't share that much in common with the You of a decade past or the future. The only thing is the assumption that the changes are small and gradual. If they really did feel that much in common with their past selves then they would not consider killing them and taking their place that easily.

The Cutie - 4/5

People call drugs an empty pleasure. Virtual Reality, games, all empty pleasures. They seem to draw these imaginary lines over what is real and what is not. What can give acceptable pleasure. But the truth is that in all these cases it is the same pleasure. Any thing which society might point to as meaningful pleasures can be reduced down to the same primitive urges. Child birth, Sacrifice, Love, Respect from community, Art, etc are all promoted or rather allowed because of other benefits we collectively gain from people engaging in them. This all done to ensure order and cohesiveness is present in society. Shame is used as a whip and culture are much needed shackles on the animal known as man. Allowing us to cooperate and compete peacefully.

The other sources of pleasure are actually just as real but can hurt your health in the long run, make you unproductive, keep you addicted. If we can manage to control these negative effects, then they are on the same level as other goals we set for ourselves. It can also sometimes be locally worth the tradeoffs involved if enough people betray to pick a locally optimal choice, it can hurt everyone globally.

... it had multiplied a thousandfold my own longing for parenthood, intensifying it into an almost physical pain. OK, OK, so it’s biologically programmed into us to love babies. So what? You could say the same about ninety per cent of human activity. It’s biologically programmed into us to enjoy sexual intercourse, but nobody seems to mind about that, nobody claims they’re being tricked by wicked nature into doing what they otherwise would not have done. Eventually someone is going to spell out, step by step, the physiological basis of the pleasure of listening to Bach, but will that make it, suddenly, a ‘primitive’ response, a biological con job, an experience as empty as the high from a euphoric drug?

Then one other idea that is already gaining ground in today's world - veganism is referenced here. How we humans value lives, is not according to the capacity to feel pain, nor their utility to us, but to how much human like intelligence they have. If they can communicate with us, cooperate with us. What rights do we grant other beings that share this world with us. To what extent do we grant them our attention? I think these questions are worth thinking about.

Into Darkness - 4/5

The memoryless propery of the exponential distribution is fascinating. Human instinct makes us feel like the time elapsed matter, that the radioactive nucleus is now more likely to decay. But nope, it does not remember. It cannot. So we can never know for sure if the decay will ever happen in a finite period of time.

This story also talks about how if a directional restriction was placed, how it would look like darkness, as light would not move towards us from the centre, we could not hear from them. Corners pointing to the centre would be deadly. The air pressure would build up over time. Pull someone into the centre would not be possible since even information can't travel outward. He took an idea and ran with it, so respect!.

Appropriate Love - 4/5

There are times when our principles hit against real walls of scarcity. We don't have the resources to give everyone a life of dignity, so how do you handle that gap? One of the main differences between a communist outlook and capitalist outlook is here. Where communists might say, let us give more people that dignity by taking away from the wealthy. Try to ensure a minimum standard. But capitalists let the market decide who gets access to what resources, earn the money required to educate your family, for healthcare, for food. Don't expect handouts. Don't penalize those who work hard and earn more and contribute more value. This idea was touched upon in this story briefly,

The solicitor shook her head. ‘The technology exists to give just about anyone — however sick, however old, however badly injured —a perfectly normal life. But it all costs money. Resources are limited. Even if doctors and medical technicians were compelled to provide their services, free of charge, to whoever demanded them . . . and like I said, there are laws against slavery . . . well, someone, somehow, would still have to miss out. The present government sees the market as the best way of determining who that is.’

It happens to some of us that we grow numb to some biological signals over time. After the 10th breakup, you grow jaded to the prospect of love. After a dozen children, I am sure the mother would treat the next child much differently compared to a fresh mother. On top of this, if you think about these special feelings and analyze them, you gain the power to override them. See them for what they are, understand what drives the courage and altruism. Why you feel kinship for them, why you feel such strong emotions. Increasingly you can see yourself turn cold, robotic and analytical. When reason triumps over instinct like this, you lose some stuff and gain others. It is hard then to go back to your innocent self, it is even harder to want to go back to being delusional since you feel more free, you feel like you have special insights into things most people lack. So regrets are rare. This is a beautiful idea that this story highlights at the end.

Sometimes when we’re together, and I see in his eyes the very same helpless passion that I’ve lost, I’m tempted to pity myself. I think: I was brutalised, no wonder I’m a cripple, no wonder I’m so fucked up.
And in a sense, that’s a perfectly valid point of view — but I never seem to be able to subscribe to it for long. The new truth has its own cool passion, its own powers of manipulation; it assails me with words like ‘freedom’ and ‘insight’, and speaks of the end of all deception. It grows inside me, day by day, and it’s far too strong to let me have regrets.

The Moral Virologist - 4/5

The best part of this story is the idea of how humans have used whatever technology they had access to at that time to reinforce cultural attitudes. Usually the cultural rules are enforced using respect, status, shame etc. But in response to this, often countercultures pop into existence where people can find a community that accepts them. Now within any of these communities, people use the latest technology to enforce norms. It usually acts to amplify the old methods via technology, shame more people, more widely, force the company to fire them, follow role models and give status to people who uphold the norms etc.

So if this was just what the IT revolution enabled us to do, the upcoming biotechnology revolution can let us do so much more. This story talks about how using death as a deterrent to enforce such norms can be amplified using advances in biotechnology. It also touches on how hard it is for a human to be infalliable. How easy it is to make mistakes and now as we grow more powerful, we can't afford to make mistakes at this scale.

There is a lack of diversity in earth, we are becoming one community in the charge of the whole ecosystem, so we now have only one chance and all our eggs are in that one basket. If some band of hunter gatherers made some wrong decisions 1000's of years ago, they might have gone extinct and other bands of homo sapiens would be left to survive.

One more idea the story touched upon was how people often change definitions on the fly in order to escape defeat. It's a famous fallacy - moving the goalpost. I think this story also highlights the fact that you can be a highly competent person in your chosen field (biology) but still hold grossly incorrect views on other areas. Humans find it hard to compartmentalize things like that and often respect a famous persons views on areas that are not his domain. Most celebrity influencers... I'm looking at you.

‘I know you don’t give a damn what I think, but I’m going to tell you anyway. You are the saddest, most screwed-up man I’ve set eyes on all week. So, you’ve chosen a particular moral code to live by; that’s your right, and good luck to you. But you have no real faith in what you’re doing; you’re so uncertain of your choice that you need God to pour down fire and brimstone on everyone who’s chosen differently, just to prove to you that you’re right. God fails to oblige, so you hunt through the natural disasters — earthquakes, floods, famines, epidemics — winnowing out examples of the “punishment of sinners”. You think you’re proving that God’s on your side? All you’re proving is your own insecurity.’

Closer - 5/5

There is this thing that authors can do. Start the book with a line and end the book with the same line. You can read the same line minutes later and now with the added context the story provides, it means so much more. While it sounded like a aphorism in the first read. You end up leaving the story behind, appreciating the depth of meaning the author was trying to convey.

This story is awesome ok?! Look initially I found it hard to identify with Michael since it is not possible to know for sure in the ideal sense that he seems to want. We all take the existence of other consciousness on faith, to stay sane and just function. There is enough evidence to suggest this is the case, as Michael says,

It was true that every brain, and hence every jewel, was unique - but there was something extravagant in supposing that the nature of consciousness could be radically different between individuals, when the same basic hardware, and the same basic principles of neural topology, were involved.

We share too much in common, the hardware, the sensory data, the genes, culture. It would be huge surprise to me if subjective sensations - Qualia was that different for each of us.

The limitations of language is another grand idea worth thinking about. How it shapes your thoughts. The tools (language) you have at hand to turn your abstract notions into concrete words partly decide the content that gets communicated. Also the axiomatic set of ideas used to construct meaning for all words depend on the extent of shared external circumstances and observed actions, otherwise all words would just be defined in terms of other words in a circular fashion. The foundation would be those words we can agree on to mean something we all sense in the same way.

No literature, no poetry, no drama, however personally resonant I found it, could ever quite convince me that I’d glimpsed the author’s soul. Language had evolved to facilitate cooperation in the conquest of the physical world, not to describe subjective reality. Love, anger, jealousy, resentment, grief - all were defined, ultimately, in terms of external circumstances and observable actions. When an image or metaphor rang true for me, it proved only that I shared with the author a set of definitions, a culturally sanctioned list of word associations.

Ok, another gem of an idea is how to confront the reality of immortality. I consider myself a curious person but I don't think my curiosity can sustain me for too long, I can imagine myself getting worn out mentally.

When the technology became available it was Sian’s idea, not mine, for us to try out all the fashionable somatic permutations. Sian was always impatient to experience something new. “If we really are going to live forever,” she said, “we’d better stay curious if we want to stay sane.”

So much so that we can turn very callous, end up aiming for such inhuman highs that soon we will not be able to relate. I don't think I am that high on Openness to want that.

“Anything’s bearable - so long as it’s finite.”

Does our brain really have modular parts, seperate for memory and personality? How many lies sustain relationships? How we seek out company to not feel lonely, but at the end of it the closer we are to our partner the more we understand her, we become one and the loneliness comes back if we lose our individuality.

Friction in a relationship is the way that we find compromises to adjust ourselves to become compatible. These fights smoothen out the hard edges and we slowly become more similar because of the dissonance.

It was a very peculiar reminiscence. Almost everything seemed at once vaguely surprising and utterly familiar - like an extended attack of deja vu. It’s not that they’d often set out deliberately to deceive each other about anything substantial, but all the tiny white lies, all the concealed trivial resentments, all the necessary, laudable, essential, loving deceptions, that had kept them together in spite of their differences, filled my head with a strange haze of confusion and disillusionment.

Unstable Orbits in the Space of Lies - 5/5

Ok, I swear I had a similar idea sitting around in my head. In this story it is really well fleshed out, I had vaugely thought of anthropomorphizing these values and represent the fight to convert followers, assimilate with other values to form hybrids, struggle to maintain coherence, etc - much more concretely with actual characters - Gods if you will.

All across the city, competing belief systems fought for allegiance, mutating and hybridising along the way . . . like those random populations of computer viruses they used to unleash against each other in experiments to demonstrate subtle points of evolutionary theory. Or perhaps like the historical clashes of the very same beliefs — with the length and timescales drastically shortened by the new mode of interaction, and a lot less bloodshed, now that the ideas themselves could do battle in a purely mental arena, rather than employing sword-wielding Crusaders or extermination camps. Or, like a swarm of demons set loose upon the Earth to possess all but the righteous . . .

The whole idea of making use of momentum and how you trace "orbits" around these attractors is delightful. I give it 5 because of how much the story resonates with me, it is crazy how all this story claims is a new mode of interaction that caused the very same clashes that always happens to move to a faster time scale.


I am sad to find that I am at the end of this book. I will definitely check out his other books (I have heard Permutation City is really good). Do let me know what you thought about the book in the comments below.