The thirty-third volume, by Danhui Li and Yafeng Xia, Mao and the Sino-Soviet Split, 1959-1973, is the follow-on to the earlier book in the series by Zhihua Shen and Yafeng Xia, Mao and the Sino-Soviet Partnership, 1945-1959.  The earlier book traced the emergence and record of the Sino-Soviet alliance in the 1950s, whereas Li and Xia discuss what happened after that alliance broke down.  Drawing on a wealth of recently declassified sources and memoirs from China and numerous other countries, including Russia, the authors show how the relationship between China and the Soviet Union moved from acrimonious polemics and fierce competition for the allegiances of Communist and Third World countries to outright military clashes in March and August 1969, killing hundreds of troops.  The book emphasizes both the domestic and the external dimensions of the Sino-Soviet split, including the impact of the disastrous Great Leap Forward on Mao’s foreign policies, followed by the chaotic violence of the Cultural Revolution and its radicalization of China’s hostility toward the USSR. The book also analyzes the momentous decision by Mao to seek a rapprochement with the United States, reversing extreme antagonism he had earlier embraced.  The book sets the scene for a third volume covering Sino-Soviet relations through the end of the Cold War and the demise of the Soviet Union.