Given the practical problems of following the development of offending and antisocial behavior in a single cohort of people from birth to the mid-twenties, Farrington, Ohlin, and Wilson (1986) have proposed following several cohorts for a few years each to profile development from birth to the mid-twenties. The current project began its design from this proposal and elaborated upon it. The proposed design of the current project involves seven cohorts, beginning at birth and at ages 3, 6, 9, 12, 15, and 18, with each to be followed for 8 years. The 8-year followup will permit conclusions about development from the prenatal period to age 25, and after only a 3-year followup, provisional conclusions could be drawn about development from the prenatal period to age 20. Experimental interventions will also be included in the design. Details are provided on sample selection and the collection of data on the communities in which cohort members live. 2 references.