The Police Assaults Study (general) analyzed assaults against police in five south-central States during 1973. Information was obtained by a comprehensive questionnaire completed by police personnel. Using the same questionnaire, the International Association of Chiefs of Police (IACP) collected data on robbery-related police assaults and on ambush attacks against police officers during the period September, 1972, through August, 1973. Both IACP studies were based on data collected nationwide. For all studies, an assault against an officer was defined as 'any overt physical act that the officer perceives or has reason to believe was intended to cause him harm'. A police assault was termed an ambush if there was suddenness, surprise, and lack of provocation by the officer immediately prior to the attack. General police assaults were found to be unplanned and usually arose out of an emotional or stressful situation. There was generally much opportunity for interaction between officer and assailant prior to the assault; alcohol often played an important role. Robbery-related assaults developed out of robber's efforts to avoid police capture, and ambush attacks were usually premeditated attempts to cause harm to the officer. Data are presented on the types of assaults according to location, hour of the day and day of the week, season of the year, the number of other officers present, height and physical build of officers, height and physical build of assailants, race of officers and assailants, age and sex of assailants, occupation of assailants, assailant involvement with alcohol and drugs, direction (front, side, etc.) from which assaults originated, whether the assailant was known by the officer, level of violence and weapons used, and injuries inflicted on officers and assailants. References are provided.