It’s entirely appropriate that a former National Geographic writer’s first book should chronicle Teddy Roosevelt’s 1912 South American river excursion. Besides inadvertently introducing adolescent boys to native female anatomy, Geographic specializes in the no-frills, high-adventure writing at which Candice Millard proves to be expert. Roosevelt, crushed in his bid for a third presidential term, opted to journey down a dangerous and previously uncharted tributary of the Amazon — a near debacle that almost killed both Roosevelt and his son Kermit. Cursed by incredibly poor planning, the expedition barely survived disease, cannibalistic tribes, and the constant threat of boulder-stuffed rapids. The River of Doubt, Millard’s sober account, is as claustrophobic as a walk through the densest jungle, and as full of vigor as Roosevelt himself.