This is a work of fiction but some of its themes and subjects have their origins in the real world. Accordingly, I would like to express my indebtedness to books and articles by the following writers, scientists, and thinkers that have been particularly helpful and instructive: Oliver Rackham, Morris Kline, Michael Ghiglieri, Jane Goodall, John Archer-Thompson, Ann Carreck, Laurie Buxton, Michael Guillen, W. V. Quine, Shirley Strum, Thomas Nagel, and Stephen R. L. Clark.