The mind-body problems are widely seen as the great remaining challenge to science and philosophy. Why and how did matter evolve to take on the quality of mind? The author takes the reader to the very edges of current knowledge and back to the beginning of time, before "mind" existed, and in doing so constructs a history of consciousness. Nicholas Humphrey"s previous books include "Four Minutes to Midnight", "Consciousness Regained" and "The Inner Eye".