the spring of 1966, nearly 50,000 Chinese soldiers were in North Vietnam, although Beijing did not officially acknowledge their presence. Some Chinese People's Liberation Army anti-aircraft units actively engaged U.S. air- craft in combat.
"Most probably," Garver writes, "Chi- na's policy toward the Vietnam War was not governed hard and fast principles, but evolved in response to U.S. actions and other international developments." Never- theless, during the critical mid-1960s...