The twentieth book, The Legacy of the Cold War: Perspectives on Security, Cooperation, and Conflict edited by Vojtech Mastny and Zhu Liqun, traces the military alliances that existed during the Cold War, including NATO and the Warsaw Pact but also the important security relationships the United States had with countries like Japan, South Korea, Australia, and New Zealand.  The authors also consider why nearly all of these alliances — the Warsaw Pact is the only exception — survived and, in the case of NATO, even expanded after the Cold War ended.