The position of rational egoism centres upon the thought that the rational thing to do must be to pursue one's own self-interest. Focusing on the work of Hobbes and Sidgwick, this book is an extensive history and evaluation of rational egoism. They are, after the ancients, the foremost exponents of rational egoism. He also considers other figures - Grotius, Samuel Clarke, John Clarke, Butler, Hume, Reid, Kant, Paley and Bentham - and a related position: the instrumental theory of rationality. Robert Shaver's conclusion is that none of the arguments for rational egoism or the instrumental theory are cogent. This is an important book not just for historians of philosophy but for all readers in philosophy or the social sciences interested in theories of morality and rationality.