OFFICIAL VIOLENCE--WARS, CAPITAL PUNISHMENT, THE SHOOTING OF LOOTERS, THE BEATING OF PROTESTERS--GENERALLY IS ABSENT FROM DISCUSSIONS OF VIOLENCE AND AGGRESSION, POSSIBLY BECAUSE THE PUBLIC, INCLUDING SCIENTISTS, HAS BEEN SOCIALIZED TO VIEW THESE ACTS AS LEGITIMATE. YET MANY IMPORTANT QUESTIONS ABOUT OFFICIAL VIOLENCE AND ITS CONSEQUENCES AWAIT ANSWERS. ONE ASPECT OF OFFICIAL VIOLENCE IS EXPLORED IN AN ANALYSIS OF DATA ON HOMICIDE RATES BEFORE AND AFTER WORLD WARS I AND II, THE VIETNAM WAR, AND 11 OTHER WARS. THE ANALYSIS, WHICH DRAWS ITS DATA FROM A FILE CONTAINING STATISTICS ON 110 NATIONS AND 44 CITIES FOR 1900 TO 1970, FINDS THAT WARRING NATIONS ARE MORE LIKELY THAN NONWARRING NATIONS TO EXPERIENCE POSTWAR SURGES IN HOMICIDE RATES. THESE INCREASES OCCUR DESPITE MASSIVE WARTIME LOSSES OF YOUNG MEN AND ARE PARTICULARLY COMMON AMONG NATIONS WHOSE WARTIME INVOLVEMENT HAS BEEN GREATEST, IN TERMS OF BOTH DURATION AND NUMBER OF MEN KILLED. THE INCREASES IN HOMICIDE RATES IN WARRING NATIONS ARE COMMON AND PERVASIVE. THEY OCCUR AFTER LARGE AND SMALL WARS, IN VICTORIOUS AND DEFEATED NATIONS, IN NATIONS WHOSE POSTWAR ECONOMIES ARE IMPROVED OR IMPOVERISHED, AMONG VETERANS AND NONVETERANS, AMONG MEN AND WOMEN, AND AMONG SEVERAL AGE GROUPS. THE HOMICIDE RATE INCREASES APPEAR TO BE EXPLAINABLE BY ARTIFACTS OR BY SOCIAL CHANGES THAT HAPPEN TO COINCIDE WITH WARS. INSTEAD IT SEEMS THAT THE LINK BETWEEN WARS AND HOMICIDE RATES ILLUSTRATES AN IMPORTANT CONSEQUENCE OF OFFICIAL VIOLENCE AND INDICATES THAT THE VIOLENT ACTS OF INDIVIDUALS MAY IN PART BE CATALYZED BY THE VIOLENT TIMES IN WHICH THEY LIVE. SUPPORTING DATA ARE INCLUDED. (LKM)