Rockford flipped to a random page in “The Man Who Tried to Save the World” and read a few paragraphs. Afterward, he told me he didn’t think he could read the whole book. “All that Tom Clancy stuff is one thing when you know it’s not real,” he said.

Scott Anderson’s book about “the dangerous life and mysterious disappearance of” disaster-relief specialist Fred Cuny isn’t fiction, though, and that’s what makes it so frightening and so compelling.