In terms of the predisposition to delinquency, strain theory points to certain features of the social environment, intervening mechanisms, and individual traits that are neglected by other theories. It is the only theory to focus explicitly on negative relations with others, and it considers several types of negative relations that are outside the realm of control and learning theories. The author believes that strain theory has become progressively broader, examining more types of strain and focusing on the explanation of delinquency in all social classes. He also indicates that strain theory emphasizes negative relations with others, specifically negative emotions such as anger and frustration. Strain theory is compared with social control, self control, and differential association/social learning theories. The unique contribution of strain theory in explaining crime and delinquency is highlighted. The paper concludes by speculating about the interrelationship between strain and other psychological theories. 48 references and 8 notes