Publisher's Note rofessor Toshihiko Izutsu (1914-1993) is Japan's foremost scholar of Islam and his works cover wide areas of Islamic studies which include the Qur'an, oriental philosophy including Islamic philosophy, and theology. This book is the fourth in a series of his works re-issued by Islamic Book Trust. First published in 1971 by the Keio Institute of Cultural and Linguistic Studies, Keio University, Japan, this book has been out of print for some time. We hope its republication at a time when both Muslim and non-Muslim scholars are showing a renewed interest in Izutsu's works will lead to better appreciation of his scholarship and contribution to Islamic thought. We are indebted to Mrs. Toyoko Izutsu, widow of Prof. Izutsu, for granting us permission to bring out this edition. We are thankful to Mr. Hiroshi Sakagami, President of Keio University Press, without whose understanding and cooperation this edition would not have been possible.