This book is a coverage of the Mahayana Buddhistic logic of the school of Dignaga. It is in fact the most important work on Buddhist logic ever published. A classic of oriental research, it is founded on a thorough study of original Indian and Tibetan compositions by the great Buddhist logicians. The author was one of the leaders of the St. Petersburg school that did monumental work in the field of Indology during the first quarter of this century.