Data on the boys' criminal behavior are related to their families' social position and composition and to background and behavioral characteristics from early childhood. The results indicate that the proportion of variance of criminal behavior accounted for by the background and individual variables is small, in most analyses below 15 percent. The percentage of variance can be increased, although not drastically. Thus, the fairly loose relation between juvenile delinquency and background variables from early childhood is an important quality of delinquency. Tables, diagrams, notes, and nine references are supplied. (Author abstract modified)