PREFACE
This translation was originally made from the second (1949) German edition, but in preparing it for the Press occasion has been taken to include the changes incorporated into the third (1957) German edition, including the Retrospect 1956.

A. BASIC NOTIONS
I. We have no autograph manuscripts of the Greek and Roman classical writers and no copies which have been collated with the originals; the manuscripts we possess derive from the originals through an unknown number of intermediate copies, and are consequently of questionable trustworthiness.