In May 1938, W. H. Auden and Christopher Isherwood found themselves near Meixi, inland from Shanghai, being escorted to the front of the Second Sino-Japanese War. Tyros to China, the two Englishmen were glad to be joined by a seasoned compatriot, a Times correspondent who handled everyone from coolies to generals with just the right touch and who, over dinner, “punctuated the conversation in truly Chinese fashion with a resounding belch,” as Isherwood writes in Journey to a War. Grateful for his expertise, Auden and Isherwood were also somewhat in awe of him, and rather tickled to be out on the road with “the Fleming Legend.” It wasn’t only that Peter Fleming was one of the most dashing and popular authors of the decade, but that they were seeing him so gloriously in character, embarked on a hastily launched trek of some danger in remote parts, marching “indefatigably ahead, with his tireless, springy stride,...