This books offers a slant on the subject of evil that goes beyond the treadmill ideas served up by religious fundamentalists, criminologists, and moral philosophers. The author, a bestselling field naturalist, contends that evil is a force of nature, a biological reality. Using the standard of Aristotelian ethics, he writes: "If good can be defined as that which encourages the integrity of the whole, then evil becomes anything which disturbs or disrupts such completeness. Anything unruly or over the top. Anything, in short, that is bad for the ecology." Marshalling all kinds of fascinating illustrative material from the animal world, Watson shows how the genes are mean-spirited and xenophobic. There are keen insights offered into whale strandings, helping across species lines, and dominance disputes. Watson gives dark nature many faces and also has some important things to say about the human propensity for both good and evil.