Philip Caputo, a Pulitzer Prize-winning journalist whose bestselling, disillusioning memoir, “A Rumor of War,” about leading a Marine platoon through the sniper-riddled and booby-trapped jungles of Vietnam, entered the canon of wartime literature, died Thursday at his home in Norwalk, Connecticut. He was 84. The cause was cancer, his son Marc Caputo wrote in a social media post. The Vietnam War, which cost the lives of at least 1 million Vietnamese and 58,000 U.S. service members, generated an outpouring of fiction and nonfiction books, by some reckoning more than 3,500 titles. A few works came to be widely regarded as classics because their authors captured unflinchingly the peculiar mix of boredom and terror in combat, the ambivalence about fighting a war that often seemed pointless and unwinnable, and the disheartening malaise that followed America’s first military defeat.…