This book is intended for readers who have little or no previous knowledge of the philosophers of the Greek and Roman world, or of their literary and historical background. Naturally, I hope it may be useful to students and teachers in courses on Greek philosophy; these readers will get both less and more than they might expect. Chapters 2 to 4 by no means cover all 'the Presocratics', as they are normally conceived; on the other hand, they cover some authors and questions that deserve to be studied more often than (as far as I know) they are usually studied by students being introduced to early Greek philosophy. In Chapters 5 to 7 I devote a good bit of space to Plato and Aristotle; but I have tried to prevent them from dominating the picture, and in Chapters 8 to 11 I have sought to give some idea of both the variety and the continuity in philosophy after Aristotle.

Some passages from Classical authors are quoted in translation in the text. Readers should be warned that a mark of omission may sometimes indicate a considerable gap in the original. I use angle brackets, < . . . >, to supply words left unexpressed, but clearly intended, in the original. I use square brackets, [. . . . ], for explanatory interpolations that are not meant to be part of the translation. Square brackets sometimes appear around authors' names in the Notes, to indicate spurious or doubtful works.

I do not provide a systematic historical outline; but I have tried to give the dates of major philosophers at reasonable intervals in the text, and they are repeated, together with the dates of other authors cited, in the index. It will be obvious that many dates of philosophers are imprecise, or unreliable, or both ('fl.' ( = floruit) indicates some specific evidence of the person's being active in the year or years given). I have usually added BC or AD to dates only where there seemed to be some danger of confusion.

Since this book results partly from my own attempts at teaching in this area, I have benefited from the stimulating and thoughtful questions and comments of many undergraduates, and from . . .