I would like to reiterate my recomendation to not start with Consider Phlebas.
The readers get a distorted and limited view of what the Culture is, how it operates, or why it’s compelling, which can put people completely off reading the other books. Later Culture novels, such as The Player of Games or Use of Weapons, offer nuanced explorations of morality, politics, and post-scarcity society. Consider Phlebas, in contrast, leans heavily on action and set-pieces at the expense of the rich philosophical underpinnings that define the series.
It is also by far the worst written of the series both when it comes to pacing and plotlines, especially the part taking place on Vavatch is outright offputting and completely irrelevant to the story (and I usually skip the whole thing when I re-read the book).
It is actually a very important part of both the book and the entire world building that it is The Culture that declares war on the Idirans.
it's actually not the culture that declared war, did you maybe skip the part where the
Idirans declared on the culture when you were too annoyed by the part describing how Vavatch orbital (which is non-culture) has some people who descended into cannibal doomsday cultism as the front lines of the war get closer? It was
absolutely a defensive war. once at war, they rapidly armed and surprised their enemies as to the ferocity with which they were willing to defend their utopia.
*edit: I was wrong. it was a liberation war declared by the culture, the lines blurred for me between JUSTIFIED and defensive.
i will reiterate that the best way to be introduced to the culture is to FIRST hear its enemies attack it, and only then arrive at the culture like an oasis in the middle of an awful galaxy you just had to march through. and then in the next book, Player of Games, you have that oasis to quench your thirst. it is precisely because Consider Phlebas is nothing like the other books that it is best to get it out of the way FIRST. this is also further reinforced by the fact that this war is the single most important historical event in the entire history of the culture and possibly the galaxy, and the only one ever repeatedly referenced in other books. by getting it out of the way FIRST, you then feel the passage of time as it fades from your memory, and the references to it later will have the correct impact.
furthermore, even if you have a "pet order" you prefer, it is always best to let someone's first exposure to any series be the intended order of the author and stop influencing people's first experience negatively in this way. if they want to change the order on second reading, let them. but the first time you read these ten books, it should be as they were published.
Use of Weapons is an absolutely AWFUL recommendation as first, please never recommend that first. it is the most traumatizing of the books and has massive emotional impact, but traumatizing is not what the first experience with the culture should be, and the impact is lessened or twisted if you don't already love the culture. I have NEVER heard ANYONE recommend THAT first. What is wrong with you? lol. Player of games I have heard before, but Use of Weapons? WHAAT? If any book will ensure your reader never reads another culture book because they read this one first when they were not ready, it's use of weapons. Amazing work, ruined completely because you recommended it be read in the wrong order. It is third. Read it third.