I have completed every book quest, renovated every book shop and bought every book they have. I've also gone back to Cappadocia by replaying memory 7-2 and bought all the books there.
I still don't have the "Sage" achievement - the description is Collect all available books so it seems like I should.
Am I missing something? If so then what?
Is this achievement broken? If so then is there any way to fix it?
It seems odd that a triple-A title like AC:R would have a bug that makes it impossible to complete it.