When this book was first published in 1960 The New York Timescommented: "[Mr.] Brzezinski...is uniquely qualified to sift the scattered and often seemingly contradictory data on this subject...the volume is marked by unusual insight, richness of information, and stimulating thought." Mr. Brzezinski who is on leave from his post as Professor and Director of the Research Institute on Communist Affairs, Columbia University serving on State Department's Policy Planning Council, has revised and updated his important study wherever necessary and added three new chapters on recent developments. He gives particular attention to the Sino-Soviet dispute.