The author of Stiff and Packing for Mars here explores the science of keeping human beings intact, awake, sane, and un-infested in war. Mary Roach dodges hostile fire with the U.S. Marine Corps Paintball Team as part of a study on hearing loss, learns why a zipper is a problem for a sniper, and visits a studio where amputee actors help prepare medics for the shock of combat wounds. Roach also answers such questions as: Why is DARPA interested in ducks? How is a wedding gown like a bomb suit? And why are shrimp more dangerous than sharks?