Emir said: This way everyone lives in a body of a kind for a while, and then leaves its body behind so that it can be remade for someone else. That's a very simple explanation, but it will do for now. Then all new life has a chance to live, and lots of room. Then we each take turns, so we can come back on new bodies when there's room available.
p. 99 - Emir's Education In The Proper Use of Magical Powers (1979)