The individuals who are the focus of this book were originally part of one of the largest medical projects over conducted in this country. In 1957, the National Institute of Neurological Diseases and Stroke launched the Collaborative Perinatal Project, a nationwide study of biological and environmental influences on pregnancy, infant and childhood mortality, and physical, neurological, and psychological development. Nearly 60,000 pregnant women participated in the study between 1959 and 1966 in 15 different medical centers. Examination of the study children from the time of their birth through age 7 continued until 1974, completing a total project cost exceeding 100 million dollars. (Further description of the Perinatal Project may be found in Chipman et al., 1966; McFalls, 1976; Niswander and Gordon, 1972.)

In 1978, the Sellin Center for Studies in Criminology and Criminal Law at the University of Pennsylvania was awarded a grant by the National Institute of Justice to examine those Perinatal Project children who were born in Philadelphia. As part of the grant, public school and police record data were collected on a total sample of about 10,000 youths. For 10 years, detailed data have been organized and analyzed on the subsample of nearly 1,000 youths who constitute the subjects for this book. These youths, who are now young adults, have grown up with the Biosocial Project. This chapter provides an in-depth look at the children who were originally selected for study, the measures analyzed on them, and their juvenile and adult crime histories.