This book explores the idea of human nature and the many understandings of it put forward by such diverse figures as Aristotle, Rousseau, Marx, Freud, Darwin, and E.O. Wilson. Each chapter looks at a different theory and offers a concise explanation, assessing the theory's plausibility without forcing it into a mould. Some chapters deal with the ideas of only one thinker, while others (such as the chapters on liberalism and feminism) present a variety of different positions. A clear distinction is made between theories of human nature and the political theories which so often follow from them.

For the new edition, Loptson has addressed the new developments in the rapidly expanding genetic and paleontological record, as well as expanded the discussion of the Christian theory of human nature by incorporating the ideas of the Marx scholar and social theorist G.A. Cohen. The new edition has also been substantively revised and updated throughout.