Book of the Stars — Ian Watson

Trapped by the evil Edrick in a locked room, Yaleen is cold-bloodedly murdered. But it is not the end of Yaleen's story, for she is given a second life - a reincarnation on Earth as a 'cherub'.

Soon she encounters Godmind, the megalomaniac artificial deity which controls life on Earth - and maintains a brutal labour colony on the Moon for any who dare to rebel. Bit by bit, Yaleen comes to understand the horrifying project of the Godmind...