Anathem by Neal Stephenson.
Typical door-stopping length novel by Stephenson. Fascinating story of an "avout", Fraa Erasmas, who lives in a "concent" on the planet Arbre. As the story opens, Erasmas is going to take vows to live his life in the Concent of Saunt Edhar.
Stephenson has his characters review, well, basically, all of Western Civilization. There's a whole lot of philosophy in there, which he manages to make incredibly interesting. As one reviewer said, " The more you know about history and ancient Greek thought the more you will be blown away by Anathem; and that is before the correlations to more recent philosophy and an extended meditation on zero-gravity navigation. A re-imagining of intellectual history, only Neal Stephenson can make the fine points of esoteric philosophical and intellectual minutia so much fun to read."
I really enjoyed it, but I can see that some people might find it dull. But I highly recommend it.