One of Ms. Buchan’s great contributions to the history of the Flying Tigers is to debunk the self-promoting story that Chennault peddled in his postwar memoir, “Way of a Fighter” (1949), which saw him arriving in Washington from China at the end of 1940 and, as if by magic, single-handedly creating the AVG over the course of the next few months. Historians and writers, including this reviewer, have largely cleaved to that story ever since. Ms. Buchan presents a corrective account that is more complicated, provocative and interesting-and probably more accurate.