I read this book about 18-Aug-2003. I've read this book before. The book is copyright 2002. This note was last modified Wednesday, 20-Aug-2003 13:52:20 PDT.
This note contains spoilers for the book.
Hooray! Another Gre Egan book. (Yeah, I know, I'm a bit late getting to it. I even knew it existed most of the time).
With the exception of Teranesia, which I found repetitive and not terribly interesting, I've been quite to extremely fond of Greg Egan's books. I seem to especially like the most far-out AI hypothetical societies. Distress and Diaspora really turned my crank, for example.
This is another one of them. Not the same, of course, but that far out. Even the embodied don't use biological computers anymore, they all run on Qusps, quantum processors that make sure they're in a collapsed state whenever they reach an actual decision. People back themselves up, and some move between embodied and pure virtual frequently. There's no FTL travel, but sometimes when a Traveler leaves a place the whole town, or planet, will run themselves slowly so they're still pretty much the same when he comes back.
Less than 50 pages into it, they've made a fundamental change to the underlying quantum structure of reality, which is propagating at 1/2c (remember, this is a non-FTL universe) throughout the rest of space. This is not your father's science fiction.
There's even a website with supporting materials, for this and his other books. And quite a few of his stories online, as well.