Senior professor of social sciences at Long Island University,Brooklyn. He is the author of Negotiating with the Enemy: U.S.-China Talks during the Cold War, 1949‒1972 (2006), coauthor of Mao and the Sino-Soviet Partnership, 1945‒1959: A New History, with Zhihua Shen (2015), Mao and the Sino-Soviet Split, 1959‒1973: A New History, with Danhui Li (2018), and A Misunderstood Friendship: Mao Zedong, Kim Il-sung and Sino-North Korean Relations, 1949-1976, with Zhihua Shen (2018). He was formally a fellow and public policy scholar at Woodrow Wilson International Center for Scholars. He has also published many articles on Cold War History.