Severe behavior disorders are among the most perplexing conditions encountered by clinicians, and as a front page article in the past Christmas Day's "New York Times" illustrates ("Parents defend school's use of shock therapy"), treatment options remain a topic of contentious debate. Not all that long ago physical restraint was the only option, the goal being to make it literally impossible for affected individuals to do things like punch themselves in the face or bang their heads against walls. More recently, drugs have been used to medicate those affected, essentially restraining them chemically. These methods, though usually provided with the best intentions, do nothing to address underlying causes, and, of course, they restrained a lot more than just problem behaviors. Fortunately, there are now far better options, and while there is still a long way to go, real help is available for an ever-increasing number of affected individuals. This article discusses the development of functional behavioral assessment tools which has had an immense impact on treatment of severe behavior disorders and has contributed to the major shift in practice toward treatments based on positive reinforcement.