Consider Phlebas
Consider Phlebas by Ian M. Banks — 1987
An action packed and witty space adventure about a changer (shape shifter) caught in a war between a post-scarcity civilisation - The Culture - and the Idirans - a zealous group opposing the Culture’s hedonism on religious grounds. The first book of Banks’ Culture series.
Horza, the protagonist, is a bit too good at getting himself into and out of impossible situations quickly for my taste, which made him harder to relate to. His motivation are unclear as well, although looking back now, I think that was intentional. On the other hand, the frequent changes in scenery allow for a wide view into The Culture and various places.
I liked it, but according to some friends more familiar with the series, this book is the least “culture-y” of the bunch. So I’m still curious as to what that means exactly. :D There were some plot holes/inconsistencies, most notably the fact that their anti-gravity tech doesn’t work in artificial gravity produced by rotating orbital which leads to one character accidentially killing himself. Shortly after, there are multiple references to the technology being used on the exact same rotating orbital.