This work is an exposition of the philosophic conceptions basic to Mahayana Buddhsim as found in the Maha-prajnaparamita-sastra, a commentary on the Prajnaparamita-sutras and traditionally attributed to Nagarjuna. The sastra the earlist and most extensive work in this field is lost in its Sanskrit original and preserved only in a Chinese translation. Meaning of Sanskrit and Chinese terms are expounded concepts are made clear and supplementary materials are supplied in the notes. The study is prefixed with a short historical account of the broad lines of Buddhist philosophy in its early stage. The aim of this work is to elucidate the meaning of the Middle Way, the way of comprehension. 'Everything stands in harmony with him who stands in harmony with Sunyata, which is not a rejection of existence or of understanding but of the misconstruction of the sense of the real or the error of misplaced absoluteness which is the origin of clinging and the root of conflict and suffering. The present work has been approved for the degree of Doctor of Letters of the Visvabharati University. The author has been a teacher of philosophy for over fifteen years. He has studied the traditional and contemporary philosophies of the Far East in China. Japan, and the United States. In Japan he has lectured on Madhyamika at Otani University and the University of Kyoto.