THIS IS ACCOMPLISHED THROUGH A REVIEW OF THE LITERATURE AND A STUDY OF STATISTICS RELATING TO INCIDENTS OF SUCH VIGILATISM IN THE UNITED STATES. IT IS SAID THAT SPONTANEOUS VIGILANTISM AS A RESPONSE TO A CRIMINAL ACT MAY BE EXPECTED AFTER A CRIME HAS BEEN COMMITTED OR A RUMOR EXISTS INDICATING THAT A CRIME HAS BEEN COMMITTED, WHERE THE INTERPRETATION OF THE INCIDENT IS UNAMBIGUOUS AND CLEAR, AND WHERE THE OPINION OF THE BYSTANDERS OR COMMUNITY IS UNANIMOUS CONCERNING THE BLAME FOR THE CRIME. SUCH ACTIVITY IS MOST LIKELY IN HIGH-CRIME AREAS WHERE CRIME MAY BE EXPECTED TO BE OF SPECIAL CONCERN TO THE RESIDENTS, AND WITHIN ETHNIC AREAS WHERE PEOPLE CAN DEVELOP A SENSE OF EMPATHY FOR ONE ANOTHER. OTHER CONTRIBUTING FACTORS MAY BE A POPULATION WHICH FEELS THAT THE LEGAL PROCESS IS INADEQUATE IN DEALING WITH THE CRIME PROBLEM, AND OF GOAL-BLOCKING OR FRUSTRATION. (AUTHOR ABSTRACT MODIFIED)