Acknowledgments

This book grew out of the Gifford Lectures given at the Univer­sity of St. Andrews in February and March 1989. My thanks, first of all, to the University of St. Andrews and the Gifford Com­mittee for their kind invitation; to the Department of Classics for its hospitality and assistance in the atmosphere of wintry St. Andrews; and most specially to len Kidd for his unfailing friend­ship. The lectures have been revised; their sequence has been changed and additional evidence and arguments have been in­troduced, but the main contents and the line of approach remain as before. I am grateful to my collaborators at Zürich University, Thomas Kappeler, Eveline Krummen, and Christian Oesterheld, for their help in the elaboration of the text and notes.pd