Consider Phlebas is a science fiction novel following an alien named Horza who's been caught up in a war between the Idirans, a species of religious crusaders, and the Culture, a group of various humanoid species whose artificially intelligent machines have become so advanced that they're arguably the ones running the show. Horza is a Changer, which means he can alter his body at will, copying a person he wishes to impersonate or giving himself unique physical weaponry like acidic sweat glands. Although he's humanoid and although the asteroid his species calls home has been conquered by the Idirans, he believes the Culture to be an existential threat to biological life itself. Therefore adopting a sort of "the enemy of my enemy is my friend" mentality, he's thrown in with the Idirans, acting as an undercover agent for them until a unique opportunity presents itself. One of the Culture's most intelligent machines, intended to be the Mind of a spaceship, is stranded alone on a planet controlled by a powerful being who only lets Changers enter. Horza agrees to retrieve it in the interest of reuniting with a love interest who lives on this planet and in exchange for the possible reward of being able to leave the war with her, but an unexpected battle throws him off the Idiran ship and into space. Left alone, will he be able to complete his mission, or will he be killed before he even reaches his destination?

I think this book might best be described as a cross between an action-packed adventure through space and a war novel. There are fast-paced sections that keep you turning pages just to see the outcome of a fight or battle, portions of world-building that introduce diverse new species or incredible technology or offer a glimpse into a particular culture. There's also a growing uncertainty over which side, if either, deserves to win this war, a dawning realization of how destructive it all is. And how impersonal the destruction. Characters die for no good reason. Entire living environments are obliterated for the sake of "principles". Even those who fight the battles seem to be viewed as disposable game pieces by the leadership on either side, easily forgotten, neglected, or left to die. In fact, in the very opening scene, Horza is saved from a gruesome execution only because the Idirans need him. And they only need him because the mission comes with such unusually specific requirements. He's saved not so much by his allies as by probability.

That, I think, reflects the tone of this book very well. It's certainly not a cheerful read, but I didn't find it as heavy as a book like The Things They Carried either. Having an additional layer of fictionalization makes the conflict a bit less real, while also providing the classic sci-fi opportunity of using a hypothetical world to explore questions of ethics and philosophy. I found that it didn't delve quite deep enough for my taste, but that may have to do with the fact that I've already spent about as much time as I care to considering the nature and implications of war. I've been fortunate in my life to live in safety and not have any form of miliary service required of me. I don't have the same personal connection that others might have.

As for the artificial intelligence, there's not much time spent on concerns about what happens to human (or humanoid) life after its abilities surpass ours. Horza expresses a few ideas about this, but overall it's not as much as I would have liked given the current state of the world. Of course, this book was written in the 1980's, so there's only so much one can expect. The AI here is very human-like, each machine having its own emotions and personality and developing attachments to those around it. The main difference seems to be in the level of intelligence, at least on average. Perhaps later books in the series will explore this concept more.

Overall, I would recommend this book to those who would enjoy a dark-ish space opera. You won't find a fight between "good guys" and "bad guys", but neither will you find gratuitous violence and an overwhelming sense of hopelessness. There was one part I found fairly gruesome, but the rest strikes a good balance in my estimation. Be prepared for some long chapters and some worldbuilding that really requires your attention, but if you can handle that you'll have a good solid read. ( )

I read the first few paragraphs in a bookstore and thought it was great, read some of his writing online about the fictional universe and thought it sounded great, then read the actual book and meh.

It's just a series of misadventures that seem to have little to do with each other, none of which seem very important.

How does a superhuman AI that's so powerful in the beginning become so helplessly infantile? Even a common drone is more capable of defending itself, without any need for hyperspace computation or whatever.

A character loses a finger and no one ever notices or comments on it for the rest of the book?

Then there's the whole Fal 'Ngeestra storyline, which has so little bearing on the story that the Wikipedia editors forgot to even mention her. ( )

Would have been a four-star book but for the unforgivable sin of having an otherwise intelligent character do something mind-numbingly stupid to create a plot point.

It's lame, it's insulting, it's lazy--and consequently boring to have to wade through pages of COMPLETELY FUTILE ATTEMPTS TO BUILD TENSION BECAUSE ANYONE WITH HALF A NEURON KNOWS IT WAS STUPID AND THAT THE OBVIOUSLY BAD AND OTHERWISE AVOIDABLE CONSEQUENCES ARE COMING SO DEAR GOD JUST STOP WRITING AS IF THERE IS ANY TENSION, UNCERTAINTY OR DOUBT HERE.

I'm tempted to give the book a two for this, but it is, otherwise, a pretty good book. ( )

I feel kind of meh about this. On one hand there is a flavor of some of the older science fiction like Ringworld with the orbitals. At the the same time there is a lot of depth in many of the characters. Relationships are built, conflicts happen, there are semi-friendly enemies, discussions of children (which was eye rollingly obnoxious in its complete lack of agency of the woman), strange hints of oddness with a species...
and then...
almost everyone dies.

Seriously just about everyone. Even the surviving Culture agent kills herself in the epilogue blurb.

It just leaves me with a ‘what was the point of all this’. And maybe that was the point of the story, but in that case it was a bit annoying.

It really is not very satisfying as a story. ( )

This is a book that seemed to start as standard space opera and which didn't seem at first to be as good as it turned out to be. It became poignant at the end, but it was fun throughout, thoroughly described but without overdoing it. The action "choreography" was great, and it was imaginative overall. It made me want to read the latter books to find out more about the Culture.
Horza's story was heart-breaking. At first I thought he would be shunted to the side for Balveda's story, since I thought it would focus more on the Culture. Instead, it focused on an individual, doomed quest that ends up shedding more light on the subject than if it had gone full-Culture from the onset.
I found Fal 'Neestra's chapters kind of pointless, though they tried to give a broader view of the Culture, they led nowhere. That was one of the few weak points.
Overall, amidst all the action (there's a lot), there are some questions that are timeless, about identity and war and fanatism. It isn't as heavy-handed as it sounds, for they're handled well in this sci-fi setting, without preaching or drawing simple parallels to contemporary events. But they're interesting nonetheless.
The later chapters in the Command System were what made the book great for me. The beginning and the middle were good, with some ups and downs, but the ending was great. It had echoes of Alien and all the great claustrophobic sci-fi horror, and the train sequence was awesomely written, gaining speed and momentum until the stunning conclusion.

I'll have to read the other books in the series to better gauge this one, but it's really good, fun but not lighthearted, and deeply sci-fi without boring the reader with too much technicisms.
( )