WHILE THREE MAJOR REPORTS PREPARED BY FEDERAL-LEVEL COMMISSIONS FOUND THAT YOUTH GANGS ARE NOT A PROBLEM OF MAJOR CONCERN, THIS REPORT INDICATES THAT YOUTH GANG VIOLENCE IN THE MID-1970'S IS A SERIOUS CRIME PROBLEM. HUNDREDS OF GANGS AND THOUSANDS OF GANG MEMBERS FREQUENT THE STREETS, BUILDINGS, AND PUBLIC FACILITIES OF MAJOR CITIES; WHOLE COMMUNITIES ARE TERRORIZED BY THE INTENSITY AND UBIQUITY OF GANG VIOLENCE; MANY URBAN SCHOOLS ARE, IN EFFECT, OCCUPIED BY GANGS, WITH TEACHERS AND STUDENTS EXPLOITED AND INTIMIDATED; VIOLENT CRIME BY GANG MEMBERS IN SOME CITIES IS EQUIVALENT TO AS MUCH AS ONE-THIRD OF ALL VIOLENT CRIME BY JUVENILES; AND EFFORTS BY LOCAL COMMUNITIES TO COPE WITH THE PROBLEM HAVE LARGELY FAILED. MAJOR FINDINGS OF THIS REPORT DEMONSTRATE THE SEVERITY OF THE PROBLEM. IN ALL BUT 5 OF THE NATION'S 15 LARGEST METROPOLITAN AREAS, LOCAL PROFESSIONALS INTERVIEWED DIRECTLY REPORTED THE EXISTENCE OF PROBLEMS WITH YOUTH GANGS OR LAW-VIOLATING YOUTH GROUPS. BECAUSE FOUR OF THESE FIVE CITIES WERE NOT VISITED, THE POSSIBILITY THAT ALL OR MOST WOULD ALSO REPORT SUCH PROBLEMS IS GOOD. THE MINIMUM NUMBER OF GANGS IS ESTIMATED TO BE 760 FOR THE 6 CITIES REPORTING SERIOUS GANG PROBLEMS (NEW YORK, CHICAGO, LOS ANGELES, PHILADELPHIA, DETROIT, AND SAN FRANCISCO), AND THE NUMBER OF GANG MEMBERS FOR THOSE 6 CITIES IS ESTIMATED TO BE 28,500. A HIGHER BUT STILL CONSERVATIVE ESTIMATE FOR THOSE SAME CITIES IS 2,700 GANGS AND 81,500 GANG MEMBERS. GANG MEMBERS, PREDOMINANTLY MALE, RANGE IN AGE FROM 10 TO 21, ORIGINATE IN LOW-INCOME COMMUNITIES, ARE PREDOMINANTLY BLACK OR HISPANIC (ALTHOUGH ASIAN-ORIGIN GANGS ARE APPEARING), AND USE FIREARMS AND OTHER WEAPONS TO KILL OR INTIMIDATE OTHER GANG MEMBERS AND THE GENERAL PUBLIC. VIOLENCE PERPETRATED BY MEMBERS OF YOUTH GANGS IS PROBABLY MORE LETHAL TODAY THAN AT ANY OTHER TIME. ALSO UNIQUE TO THE PRESENT PERIOD IS THE DEGREE TO WHICH GANG ACTIVITIES ARE CONDUCTED WITHIN PUBLIC SCHOOLS AT ALL LEVELS (ELEMENTARY, JUNIOR, AND SENIOR HIGH). FOOTNOTES, NUMEROUS TABLES, AND APPENDIXES, CONTAINING A GANG SURVEY INTERVIEW GUIDE, GANG INFORMATION TOPICS, AND SOURCES OF SOME TABULAR DATA, ARE INCLUDED. (PRG)