This is book 1 of the "Orthoganal" series.

This note contains spoilers for the book.

New Egan series, and already four years old.

Sadly, I didn't finish it. Not horrible, and maybe in a different mood it would work for me.

This one felt to me like the world-building was paramount (and that's really what Egan is known for). However, I didn't find the characters that interesting, and the worldbuilding seemed to be all in a completely from-scratch physics. In particular, the world seemed to be rather short on history internally, and it bothered me a lot that the society had what amount to internal-combustion trucks but was just starting to figure out the basic laws of physics (at the level where Newton was working).

Then it wrapped a sub-plot about rights of women in, which is certainly a current issue here world (sadly; things we thought we had settled in the 1970s have come unstuck, in addition to the inevitable things we got wrong or hadn't noticed), but the coincidence of it being an issue in that unrelated world at just the same time as in this world bothers me. Kind of like in Niven & Pournelle's The Gripping Hand, where details of how the roaming pocket computers work are revealed which just happen to relate to the big excitement about public-key encryption techniques in our world, which were just hitting the public consciousness when the book was written. Breaks suspension of disbelief for me, by emphasizing the dependency on this world.

The alternate physics is probably great if that's your thing. Light moves at different speeds dependent on color, but physical waves move at the same speed. Emitting light is part of creating energy. And a few other things, that they're starting to explain in detail. But I don't find myself feeling like digging in and trying to get used to thinking in terms of their physics, or appreciating the differences in detail.

Sadly, I think this is two or three in a row of new books from Egan that didn't work for me.