In the past two to three decades, clinicians and neuroscientists have been studying the functions of the right hemisphere. Neither hemisphere seems to be dominant in the absolute sense. Each appears to be specialized and is dominant for different functions. However, most functions require the cooperation of both hemispheres. When one is damaged, the other can often compensate for the damaged one. Lesions of the left hemisphere are associated with language (speech, reading, and writing) and praxic disorders, and lesions of the right hemisphere can result in visuospatial, attentional, and emotional disorders. The authors review some of the major behavior disorders associated with right hemisphere dysfunction and concentrate on three major types of disorders--visuospatial, attentional, and emotional. Although not all the behavioral defects associated with right hemisphere damage can be subgrouped under these three types, they are the ones most often associated with right hemisphere lesions.