It's not as good as the previous two books. Instead of theoretical physical explanations we just get interesting visual effects: a description of what might happen when the arrows of time meet. It's still a good discussion of mind-boggling ideas, it just has fewer answers than the other two. I liked the writing no less than the previous books, and the social progress of this weird world remains just as engaging as it was. I really like how Egan covers every question that may pop up in the reader's mind. In the end it was a satisfying conclusion to a superb series, just not the best book of the trilogy.