v. 1. 1928-1945, from the consequences of World War I to the end of World War II
v. 2. 1946-1962, from the end of World War II to the various stations of Cold War
v. 3. 1963-1977, from the escalation of the Vietnam war to the East Asian refugee problems
v. 4. 1978-1989, from roarings in the Middle East to the destroying of the democratic movement in China.