Many years of laboratory research provide the basic and rationale for behavior modification techniques and behavioral treatments. The behavior modification methods currently used include procedures, such as desensitivization, which are suitable for the clinic, and procedures such as the token economy, which are suitable for the mental institution. Behavior modification methods have been used to ameliorate a wide range of problems, including mutism, self-destructive behavior, inappropriate fears, and nervous habits. Behavior modification methods have also been used to teach a variety of normal behaviors, including normal speech, appropriate social behavior, and suitable classroom skills. Some fear that behavior modification methods may be used by those in power to control and manipulate others in contradiction of humanistic values. The most controversy has arisen in association with the use of behavior modification in prisons. Behavior modification programs have sometimes been used to preserve authoritarian control and discipline rather than to teach skills that would benefit the inmate. Recent legal rulings have called attention to possible abuses of the use of positive reinforcement and have extended the rights of institutionalized persons. Ethical responsibility demands that clients or their representatives be consulted about the methods and goals of programs, so they may weigh the balance of risk and benefit of any proposed program. Programs should be monitored to ensure they are effective, and those conducting the program should be accountable to those whose behavior is being impacted. Notes and a list of 53 references are provided. (Author abstract modified)