The author of Stiff, Spook, Bonk, and Packing for Mars here explores the science of keeping human beings intact, awake, sane, uninfected, and uninfested in war. Mary Roach dodges hostile fire with the U.S. Marine Corps Paintball Team as part of a study on hearing loss and survivability in combat, learns why a zipper is a problem for a sniper, and visits a studio where amputee actors help prepare medics for the shock and gore of combat wounds. Roach answers questions not found in any other book on the military: Why is DARPA interested in ducks? How is a wedding gown like a bomb suit? And why are shrimp more dangerous to sailors than sharks?