For most of the book I was pretty hooked and I kept wanting to read more. Even the huge passages of characters discussing philosophy and mathematics kept me interested and turning the pages. The theories they discussed were very thought provoking and I liked the way the mathematics was explained in a very accessible way.

The only thing I found didn't quite do it for me was the ending (spoilers): Suddenly some characters can phase between universes? They can change people's memories and/or the actual past? These bombshells were dropped and then glazed over without getting into the implications, leaving the end of the novel feeling a bit unfinished.