Although the rate of combined homicide-suicides is low compared with that for suicide alone or homicide, homicide-suicides generate much public concern. In some cases, the homicide-suicide involves annihilation of an entire family or multiple non-family members. A difficult phenomenon to study--in part because the perpetrator is dead--it is, nonetheless, crucial to attempt to advance our understanding of this tragic phenomenon from a psychiatric view. This literature review then addresses demographic variables; proposes two classifications, one based on psychopathology, the other on the relationship between offender and victim; and suggests a three dimensional analytical approach to understanding homicide-suicide: 1) psychopathology and ego deficits of the perpetrator, 2) cumulative and precipitating stressors, and 3) motivation and vector of destructive urges against self and the other victim(s). Finally, some implications for mental health clinicians and forensic experts are offered. In attempting to understand acts of homicide-suicide, inquiry into the following dimensions should be useful: Ego Weakness. What type of mental disorder(s), psychopathology, or personality traits may have contributed to the homicidal-suicidal behavior? Stressors. What type of acute and chronic stressors did the individual experience leading up to this act? Vectors. Whom did the individual select to kill and why? Were some victims more clearly primary and others secondary or incidental?