I have to admit that Permutation City is the type of novel I want to write. I think my first novelistic effort, Dirtside to Spaceside (there I go peddling it again), had a lot of interesting ideas. But one thing I need to do, if I decide to progress Dirtside past the first draft stage, is support those ideas with more solid scientific theory.

Permutation City is initially set in the years 2045-2051, in a world where humans are able to make "copies" of themselves that live in Virtual Reality systems. Rich people use this technology to continue their lives and businesses after they die, because the VR systems can interact with the real world. The main character, Paul Durham, sets about creating an alternate universe far more complex than the VR available at the time. He sells the idea to a group of billionaires, using the promise of immortality. The other main character, Maria, is one of the programmers for this. She "seeds" a world in this alternate universe in a half computing/half biological manner using the "Autoverse" - a computer simulation of a Universe with its own laws of physics.

Eventually Durham and Maria succeed in creating an alternate universe and the billionaires are copied to it. Durham is up to his 24th copy at that point, but copies himself once more to this alternate reality - called the "TVC Universe" (the capital city is called Permutation City). Maria has so far not had any copies of herself done during her lifetime, but for a sum of money she allows herself to be copied to the TVC as a systems back-up - only to be woken in an emergency. When Durham later wakes her up in the TVC, 7000 years later, she is furious and experiences mixed feelings about her copied self. 

Now this is where the book gets really complex! The inhabitants of the TVC universe are immortal and Egan's imagination runs free with the 'permutations' of this. One of the themes is a standard sci-fi one: "is a copy a human?" But the number and quality of variations on this theme is stunning. Another compelling storyline is that an alien civilization has developed by evolution in the Autoverse world that Maria created.

I better stop before I spoil the ending! I recommend you go out and read the book. It's certainly inspired me.