In this article, the author reviews the Ruff Neurobehavioral Inventory (RNBI), a self-report questionnaire designed to assess an individual's ability to function in cognitive, emotional, physical, and psychosocial domains, before and after a major illness or injury. The measure is designed to be used with men and women ages 18 to 75 who have at least a fourth-grade reading level and whose native language is English. The RNBI assesses an individual's perception of his or her own premorbid and postmorbid health in two primary domains. The intrapersonal domain assesses the individual's perception of his or her cognitive, emotional, and physical health. The interpersonal domain assesses the individual's perceived quality of life and includes subscales assessing vocational status, financial resources, spirituality or meaning of life, recreational outlets, and general support system. In addition, there is a subscale assessing the possibility of maltreatment through physical or sexual abuse. Administration of the RNBI is by self-report, and technicians or qualified personnel can administer the test either individually or in groups. Interpretation of the RNBI should be made by qualified professionals with knowledge in psychometrics, psychopathology, neuropathology, and brain-behavior relationships. The author finds the instrument to have potential for being an effective psychotherapy and rehabilitation treatment initiator. The measure shows reasonable validity with other established measures of patient functioning and is likely to differentiate important areas for treatment based on the nature of a patient's disability. The RNBI manual is comprehensive and provides ample detailed information on how reliability and validity is determined, and it provides case examples of patients. The primary limitations are a lack of studies assessing its usefulness with different patient populations and a lack of outcome studies. However, the instrument is an important development in the enhancement of neuropsychological services, and the author recommends its use both clinically and in research. (Contains 1 table.)