Isaac Levi has retired from his academic position as prestigious John Dewey Professor of Philosophy at Columbia University, and yet there is no sign that he has retired from philosophy. On the contrary, he just published a new book entitled Mild Contraction with Oxford University Press, and he continues to write papers and participate in conferences and workshops. This collection is dedicated to Isaac on the occasion of his retirement, in celebration of his exceptional contribution to philosophy in general and to the great tradition of American pragmatism in particular. It is far more than a Festschrift in the usual sense; all the papers included are substantial contributions to the understanding and appraisal of Isaac's pragmatist philosophy by leading experts on his work. They were all written specifically for this volume and appear here for the first time. I am greatly indebted to all authors for their dedication and commitment to this project, and especially to Isaac for his extensive replies to all the papers.

My own intellectual debt to Isaac is great. My first internationally published paper, written jointly with Sven Ove Hansson, who was my thesis adviser back then, addressed Isaac's theory of belief contraction. In this connection, reading his book The Fixation of Belief and Its Undoing was especially rewarding, although some of his more intricate arguments were beyond my grasp at the time.