Eight golden rules are presented which aggression assessment should abide by to reach a comprehensive assessment: (1) identifying the motivations for aggression and recognizing that motivation can change over time and across behaviors; (2) identifying the same for nonaggression, focusing on locating protective factors; (3) identifying areas of an individual's background known to relate to the development of aggression, and charting how these factors influence behavior and change over time; (4) exploring normative beliefs and the causes of hostile attribution biases; (5) exploring an offender's perception of the consequences of their aggression; (6) recognizing that aggression may have adaptive qualities and not automatically assuming therefore that the treatment target is skill acquisition or enhancement; (7) acknowledging the role of the environment in determining the negative and positive reinforcements for aggression; and (8) moving away from adopting over simplistic individual psychopathological models of understanding aggression. Human behavior is complex and the idea of having a generic assessment to cover the needs of all habitual aggressors is an impossible goal to reach. This chapter sought to illustrate the complexity of aggression assessment by describing the developmental and learning history components relevant to aggression and its motivations. References