Winning a war takes more than guns. The need to keep soldiers safe and healthy have prompted researchers to explore everything from Kevlar underwear to laundry-free uniforms and shark repellents (no luck, yet, on that front). In her new book, Grunt: The Curious Science of Humans at War, Mary Roach goes behind the scenes with the scientists trying to make life a bit better for soldiers. Previously, Roach has applied her curiosity and sense of humor to topics ranging from sex, and digestion, to