One of my favourite SciFi authors because his books are also Philosophy Fiction (PhiFi?)
The central character is an old-fashioned human (like us) in a solar system populated by post-humans of several kinds. A good story with many twists where friends and foes are hard to distinguish, right from wrong needs thinking about and a good counter-argument to aggressive atheism is woven in.

I haven't worked my way through the almost-30 pages of notes and references, a little unusual for scifi, but I will; it's interesting too. But you'll already know from the text that there is a lot of research behind this hard sciphifi book.