A Perfect Harmony: The Intertwining Lives of Animals and Humans throughout History is an informative, insightful history of animal domestication through the ages, by late ASPCA president Robert Caras, author of numerous fine works on pets and wildlife. As Caras defines it, domestication is "the shaping of a species by man, using selective breeding to replace natural selection." By studiously reviewing the origins and probable methods of domestication and the ancestry of all manner of animals, from goats and horses in the Stone Age to camels and elephants around 4000 B.C., to ferrets and cats in more recent years, Caras explains how "animals have played a vital role in man's evolutionary course."