The paper describes hyperkinesis, a common behavior problem of childhood which is characterized by symptoms which include involuntary and consistent overactivity usually with onset in early childhood or infancy, short attention span, and poor school performance. Sections touch on the following aspects: symptoms, etiology, course of illness, identification, treatment/medications (including use of stimulants), treatment/diet (such as the Feingold diet), and treatment/psychotherapy. The author concludes that clinicians need to maintain a broad, flexible attitude since various treatment approaches are effective with various individuals and since responsiveness to a specific treatment may also change over time, requiring a shift in treatment. (SBH)