The revised and updated edition of Lt. Col. Dave Grossman's modern classic about the psychology of combat, hailed by the Washington Post as "an illuminating account of how soldiers learn to kill and how they live with the experiences of having killed." In World War II, only 15 to 20 percent of combat infantry were willing to fire their rifles. In Korea, about 50 percent. In Vietnam, the figure rose to more than 90 percent. The good news is that most soldiers are loath to kill. But armies have developed sophisticated ways sophisticated ways of overcoming that instinctive aversion. The psychological cost for soldiers, as evidenced by the increase in post-traumatic stress, is devastating. This landmark study brilliantly illuminates the techniques the military uses to help soldiers kill and raises vital questions about the implications of escalating violence in our society. "Powerfully argued...Full of arresting observations and insights." --New York Times