This book, first published in 1958, examines the life and works of Avicenna, one of the most provocative figures in the history of thought in the East. It shows him in the right historical perspective, as the product of the impact of Greek thought on Islamic teachings against the background of the Persian Renaissance in the tenth century. His attitude can be of guidance to those in the East who are meeting the challenge of Western civilization; and to those in the West who have yet to find a basis on which to harmonize scientific with spiritual values.