The single most important defense against being robbed or assaulted is to be alert. Since street criminals, especially muggers and purse-snatchers, are essentially predators who spot victims, stalk them, and attack. They can sense vulnerability by noting the way a person walks, holds the head, and carries a handbag or package. Specific techniques can prevent crimes in the lobby of a building, in an automatic elavator, inside an apartment, in a car, and on bus or subway. Citizens should use such security devices as deadbolt locks, strong doors, and peepholes. Burglar alarms can also provide another line of defense, since their noise usually causes the burglar to leave. Advice on choosing a self-defense course notes the importance of emphasis on learning to deal with specific attacks to the vulnerable areas of the body and on learning how to yell. Twelve New York City schools which offer training in techniques of self-defense are described. Additional guidelines cover methods of hiring private security patrols and volunteer citizens' patrols. A discussion of potential government efforts to control crime focuses on the need for increased prison space or more imaginative sentencing, proper identification of repeat juvenile offenders, bail reform, court reform, and the need for stronger control and accountability in the entire criminal justice system. Photographs are included.