From back cover HarperPrism paperback November 1999:

It is the thirtieth century. The "world" has evolved into a vast network of probes, satellites, and servers knitting the solar system into one scape from the outer planets to the sun. Humanity, too, has reconfigured itself. Most people have chosen immortality, joining the polises to become conscious software. Others have opted for disposable, renewable robotic bodies that remain in contact with the physical world. A few holdouts stubbornly remain fleshers struggling to shape an antiquated existence in the muck and jungle of Earth.

And then there is the Orphan, a genderless digital being grown from a mind seed.

WHen an unforeseen disaster ravages the fleshers, it awakens the polises to the possibility of their own extinction from bizarre astrophysical processes that seemingly violate fundamental laws of nature. It is up to the Orphan and a group of refugees to find the knowledge that will save them all -- a search that will lead them on a quantum adventure to a higher dimension beyond the macrocosmos....