This volume began its life at a conference on Perception and Perceptual Content at the Centre for Philosophical Studies, King's College London, in May 1990. The essays by Thomas Baldwin, E. J. Lowe, Christopher Peacocke and Michael Tye were first presented at that conference. (The other paper presented at the conference, Richard Sorabji's ‘Perceptual Content in Ancient Greek Thought’, will appear in print as ‘Intentionality and the Physical’ in Martha Nussbaum and Amelie Rorty (eds.), Aristotle's de Anima, forthcoming from Oxford University Press.) J. J. Valberg's essay is an extract from his book, The Puzzle of Experience, forthcoming from Oxford University Press; it is reproduced here with permission. The essays by Michael Martin, Brian O'Shaughnessy, Paul Snowdon and myself were written especially for this volume.

I am very grateful to Richard Sorabji for the original suggestion that I organise the conference, to King's College London for the financial assistance, and to the participants at the conference for making it such a worthwhile and enjoyable occasion.

A number of people have helped me in bringing this volume to publication. Judith Ayling has been an understanding and astute editor from the outset. Bill Brewer and Jonathan Dancy read the typescript for Cambridge University Press, and offered many useful suggestions for improvements. Hugh Mellor generously gave his time and expertise in the preparation of the camera-ready copy. And finally, many thanks to Tabitha Jackson for her patient assistance with the final stages.