The dimensions described here explain how crimes co-occur in delinquent careers. Career-lines of 913 chronic delinquents, categorized as those with six or more arrests, were depicted as regression lines and classified on the basis of their fit to these underlying dimensions of crime. Criteria were established for identifying delinquent career-lines as stable, developmental, or diverse. Nine types of stable and developmental career-lines occurred frequently, accounting for over 66 percent of the chronic delinquents. The career-lines include burglary/auto theft to general delinquency, general delinquency to serious persons with burglary, general delinquency to serious persons, serious persons offenses to general delinquency, stable general delinquency career, status offenses to general delinquency, stable general delinquency career -- auto theft, general delinquency to property/petty crimes, and property/petty crimes to general delinquency. Chapter references and 3 appendixes