Sounds interesting, is the physics in the book mathematically sound/consistent? (and interesting, hopefully)

It is mathematically interesting and shows how physics behave if you change assumptions about the geometry of space-time.

Egan has copious documents on the physics of the Orthogonal universe at his website [ http://www.gregegan.net/ORTHOGONAL/ORTHOGONAL.html ]

AFAICT, it is mathematically sound and internally consistent, and very interesting.

I really like Egan's work, particularly earlier books like Diaspora and Permutation City, but find his later works unsatisfying due to poor characterisation and pace. Incandescence is a good example - I plodded through it and finished only by a real effort of will.

Does the Orthoganal trilogy work for you on that level? I'm looking for some good fiction to balance by non-fiction reading now that the nights are getting darker.

I found the Orthoganal trilogy brilliant as an experiment in character development, and extending "alternate realities" about as far as they can be extended, but they aren't as engaging as most of his other books (IMO).

I think this is more due to the fact that humans like reading about characters they can easily relate to, and Egan really pushes this boundary!

Still worth a read, and I'll almost certainly re-read them in the future.

Interesting that you mention that. I just now finished Permutation City and in my opinion it was pretty terrible ... as a work of fiction. Pace was off, characterization was horrid. I guess Incandescence wouldn't work out too well for me. Permutation City is the first Egan novel i've read though. I had no issues with his short stories though so I suppose I will stick with that format anytime I'm hunkering for some rigorous hard sci-fi.

Incidentally I read Permutation City right after Surely You are Joking Mr Feynman! While the Feynman book was an obvious page turner the Egan book was slow going. The difference to me was quite jarring and must have contributed in part to my disliking of the book.