Personal Identity is a comprehensive introduction to the nature of the self and its relation to the body. Harold Noonan places the problem of personal identity in the context of more general puzzles about identity, and discusses the major historical theories of Locke, Leibniz, Butler, Reid and Hume. Noonan then considers the topics of more recent debates, including the work of Bernard Williams and Derek Parfit, and interprets them in new and challenging ways. The second edition of Personal Identity contains a new chapter on the increasingly popular biological approach of 'animalism' and a new section exploring how recent work on vagueness impacts on borderline cases of personal identity. There is also an updated bibliography.