The science of ecology has time and again led to conclusions that have proved wrong in practice, and that have generated dubious political mores. This book puts forward the notion of a `mathematical ecology' which looks at the mathematical relationships that link the fates of all plants and animals in a natural community, but which avoids such outdated thinking as the `web of life' or `balance of nature', which implies a delicate system easily disturbed by man. The clarity of thought expressed here brings to a general audience, as well as the professional ecologist, a new understanding and appreciation of wildlife, as well as the means to make sense of and assess the steps society is taking to manage, preserve, and protect species whose fate is increasingly in our hands.