The worst thing you could do is read Consider Phlebas back pages first. Once upon a time I used to take the first and last sentences or first and last words as a brief synopsis of every book. It kinda works for the Bible. "In Amen". But to do so for Iain M. Banks celebrated sci-fi would almost obviate the great adventures contained therein.
Consider Phlebas is a space opera, something of a cowboy story with a trick ending, an amoral tale of the actions of civilizations on conflict down to the deadly combat and scheming of individuals from different parts of the galaxy.
In one way I didn't follow my own advice. I was advised to read 'Player of Games' first but didn't find this Culture book of Banks available. So I read his most recent treatment of the galaxy 'The Algebraist' and then to his very first, Consider Phlebas. There is no doubt that Banks is a much more accomplished writer now than 20 years ago and so I can see that he has clearly gotten to where he was trying to go which is to convey the essence of the practically infinite scale of galactic events and put the actions of humans in scale. He does so without making humans any larger or smaller than humans. Which is to say that in the largest scheme of things imaginable, human drama still counts for something, as it inevitably would to us humans. And in that regard Banks is an extraordinarily good sci-fi writer, standing just below Samuel R. Delany as the best ever.
But Banks gives us something one better than Neveryon which is a continuing series of novels about the Culture and it is in the matters of the Culture that Banks shines. What is the Culture? It is utopian, and infinite in the ways we are most constrained here on earth. It is a cultural empire that fights for philosophical reasons, and it is run by machines which were created by humans. They are the Minds each of which is capable of nearly god-like intelligence and they work to integrate every alien species into harmonious existence in which all sentient beings are accorded rights.
Of course not every species is interested in following the Culture's scientific and logical perfectionism, chief among them are the Idirans, a race of 3 meter triped giants who evoke the deep religiosity of a warrior cult. In fact they were a perfectly peaceful people, in total harmony with the ecology of their bountiful planet until provoked by the Culture. At that point they realized everything foreign to them as a threat and transformed into a race of annihilation still steeled by religious discipline. So war was inevitable and it is in the midst of that war that our story begins.
It is the story of a lost and crippled Mind, a planet of the dead, a Changer, an intelligence agent of the Culture and a Firefly-like crew of freebooting pirates. The Changer, allied with the Idirans, and pursued by the agent, seeks to capture the Mind from the neutral planet of the dead. He ingratiates his way into the pirate ship and the adventure takes off from there.
Phlebas is a work of great imagination whose galaxy makes extended human sense and yet is not extensively human. I suspect, that in that regard I am going to have to complete about 1000 more pages of the Culture novels to get at what Banks might be implying. To that end I have just begun Matter, his latest.
Even without that these are excellent tales of enormous scale.