Since before Plato, philosophers have puzzled over why it is that people will sometimes deliberately take the worst course of action. The book begins by examining the various theories put forward by Plato, Aristotle, the Stoics and a selection of medieval philosophers and discusses how and why later philosophers avoid the problem. In the second section, Justin Gosling argues that familiar ways of viewing the problem mislocate the apparent irrationality of weakness. The author then moves on to the traditional cases of being overcome by passion to argue for a further sense in which weakness may be thought irrational, and to open up an unusually wide field of examples for consideration.