THE GOALS OF THIS STUDY WERE TO ESTABLISH THAT ASSAULTS AGAINST POLICE OFFICERS ARE GREATLY INCREASING AND TO DEVELOP A THEORY TO EXPLAIN THEM. ACCORDINGLY, 547 POLICE OFFICERS REPORTING 359 INCIDENTS OF ASSAULT IN DETROIT, 1973-1974, WERE GIVEN INTERVIEWS AND QUESTIONNAIRES. FINDINGS INDICATE THAT REPORTED ASSAULTS, RATHER THAN REFLECTING REAL INCREASES, ARE A RESULT OF MORE POLICE OFFICERS SEEKING HAZARDOUS DUTY FOR GREATER FINANCIAL REWARD. MOREOVER, A CHANGE IN EMPHASIS IN THE POLICE ROLE FROM PHYSICAL COMPETENCE TO PROFESSIONALISM FINDS OFFICERS LESS TOLERANT OF PHYSICAL CHALLENGE. IN ADDITION, SINCE ASSAULTS ON OFFICERS ARE FOUND TO BE UNLIKE ASSAULTS ON ORDINARY CITIZENS, MERELY COUNTING THEM ADDS NOTHING TOWARD UNDERSTANDING THEM. A SOCIAL ANALYSIS OF THE INCIDENTS REVEALS NO SIGNIFICANT RELATIONSHIP BETWEEN ASSAULTS AND THE HEIGHT, RACE, SEX, OR EDUCATION OF THE OFFICERS ASSAULTED OR THOSE ATTACKING THEM. ALTHOUGH MOST ATTACKERS ARE YOUNG, RACIAL HOMOGENEITY BETWEEN OFFICERS AND SUSPECTS DOES NOT REDUCE THE NUMBER OF ASSAULTS. WHAT DOES SEEM TO CONTRIBUTE TO ASSAULTS IS AN ASSESSMENT BY CITIZENS IN POLICE ENCOUNTERS THAT THE OFFICER IS NOT PERFORMING HIS ROLE PROPERLY. MOREOVER, IN AN ENCOUNTER, AN EFFORT BY THE CITIZEN AND OFFICER INVOLVED TO RECONCILE DIVERGING IDEAS OF WHAT THE OFFICER OUGHT TO BE DOING LEADS TO VIOLENCE. SINCE FEW PERSONS ASSAULTING AN OFFICER HAVE A RECORD OF VIOLENCE, EXPLAINING THAT ASSAULTS HAPPEN IN SUBCULTURES OF VIOLENCE IS REJECTED. MOST ASSAULTS HAPPEN WHEN POLICE STOP AND INVESTIGATE CITIZENS WITHOUT PRIOR COMPLAINT ABOUT THEM. IN SUCH CIRCUMSTANCES, BOTH OFFICER AND CITIZEN EXPECT THE WORST OF THE OTHER. TABLES, FOOTNOTES, AND 46 REFERENCES ARE INCLUDED. ADDITIONAL TABLES, A QUESTIONNAIRE, AND SAMPLE FORMS ARE APPENDED.