Storyline: 4/5 
 Characters: 2/5 
 Writing Style: 4/5 
 World: 5/5 
 Mark down that number - 5 - the fifth in the Culture series. This is where it all became more than a series, more than a fun yarn, more than an above-average piece of science fiction writing. It is here, in Excession, that the barrage of technospeak aligns with inventiveness and squares with vision. Here (finally!) one realizes that this is not simply an installment, but the birth of a genre-defining work. The Culture series now has a predominate identity. It is not merely science fiction (too broad), nor is it simply a mind-dumbing space opera (as number 1, Consider Phlebas, was). Definitely not a character-driven, flowingly beautiful, speculative fiction (i.e. number 2, Player of Games). Nor is this the hip, edgy, and violent action-adventure experimenting with nonlinear narration (that was, of course, number 3, Use of Weapons). What five settles into - no, what five grabs with two hands and commands - is far future science fiction. 
 Far future science fiction. It's just the matter of providing the science fiction world with a calendar year far into the future, right? No, far future science fiction has the unique challenge of making the familiar alien. One has to take our world as we know it and make it incomprehensible enough for the reader to feel the weight of a millennia of change. But that world still has to retain some level of intelligibility lest it collapse into nonsense. Excession gives Culture a home; one that it had been in need of all along. That continuous, corrugated, and off-hand inclusion of science fiction lingo now has a purpose. This is how one describes and narrates the far future. You don't get a tutorial, glossary, or infodump to explain the terminology. It is part of the world-building; you pick it up as you move along. 
 Pulses of radiation blasted in from various directions, virtually information-free. The ship's inertial field wobbled uncertainly, then drew steady and settled again. A shell of neutrinos swept through the space around the companionway. Noises faded. EM signatures murmured to silence; the ship's engines and main life support systems were off-line. The whole EM spectrum was empty of meaning. Probably the battle had now switched to the ship's AI core and back-up photonic nuclei. 
 That is a typical passage. When the action and adventure moves into skeins, layers of space, and speed described by metric prefixes one feels pelted. Perhaps the physics-minded and veterans of a thousand science fiction tales can follow the specifics more easily. The point, though, is not to understand all the details but to be immersed in a future not only thousands of years from now but one capable of making and executing plans whose impact won't be felt for four and a half millennia in their future. The MS-DOS looking pages in experimental form might seem anachronistic or bizarre, but it was another effective way of balancing purposeful disorientation with story-moving dialogue. And finally, aside from the immense race, planet, habitat, ship, and ring world-building Banks provides, there's the culture (little c) of Culture (big C). That has been there as a highlight throughout the series and if finally finds a complementary environment in which to unfold. 
 This will make it an unapproachable work for many. Also, despite Banks's idea (and many fans insistence) that these books are independent and can be read in any order, you should read some of the first ones before this. The AIs, glanding, weaponry, color fields, and divisions within the Culture are explained well enough to make this an independent work, but you are going to be struggling to catch up on the background when you need to be struggling to keep up with the story.