THE AUTHOR PROPOSES A NEW MEASURE OF THE INCIDENCE OF DELINQUENCY: THE PREVALENCE RATE. HE DEFINES THIS RATE AS THE PROPORTION OF AN AGE COHORT THAT BECOMES DELINQUENT ACCORDING TO SOME DEFINITE CRITERION BY A GIVEN AGE, USUALLY AGE 18. THE AUTHOR THEN PRESENTS THE RESULTS OF SEVERAL STATISTICAL STUDIES OF DELINQUENCY RATES, AND REANALYZES THESE RESULTS IN TERMS OF PREVALENCE RATES. THESE RATES ARE ESTIMATED FOR RURAL, URBAN, BLACK, AND WHITE POPULATIONS BASED ON THESE DATA. THE AUTHOR CONCLUDES THAT RACE-SPECIFIC DELINQUENCY APPEARS TO BE EQUALLY PREVALENT FROM ONE URBAN PLACE TO ANOTHER, AND THAT THIS REGULARITY IN RATES IS INSENSITIVE TO CHANGE IN COMMUNITY SIZE THROUGHOUT AN ENORMOUS RANGE OF THE URBAN-RURAL CONTINUUM. FROM THIS, THE AUTHOR CONCLUDES THAT CRIME DOES NOT VARY AS A RESULT OF URBANIZATION; INSTEAD, HE CONCLUDES THAT RACIAL COMPOSITION OF THE AREA IS A MORE IMPORTANT DETERMINANT OF CRIME PREVALENCE. THE AUTHOR THEN REVIEWS SEVERAL STUDIES WHICH SUPPORT THE THEORY THAT DELINQUENCY IS RELATED TO INTELLIGENCE LEVELS. ARGUING THAT INTELLIGENCE TESTS ARE VALID FOR VARIOUS RACIAL AND SOCIOECONOMIC GROUPS, THE AUTHOR INFERS THAT THE HIGHER DELINQUENCY RATES FOUND IN SOME MINORITY GROUPS ARE THE RESULTS OF THE LOWER INTELLIGENCE LEVELS OF THESE GROUPS. FINALLY, THE AUTHOR EXAMINES SOME ENVIRONMENTAL AND CULTURAL FACTORS WHICH MAY INFLUENCE THE INTELLIGENCE MODEL OF DELINQUENCY WHICH HE HAS PROPOSED.