There were six major findings. First, the majority of girls in the project's two studies were involved in some form of delinquency at some time during late childhood to late teens. For the majority of these girls, delinquency involved status, public-disorder, or minor offenses; some girls, however, were involved in serious property and violent offenses. Thus, there is sufficient reason for concern about the delinquent behavior of girls, warranting the provision of services and interventions for girls. Second, there was no one developmental sequence that described girls' delinquency. Individualized intervention strategies are apparently needed. Third, for most girls involved in serious offending, it was age limited to 1 or 2 years. The researchers recommend that unless interventions have shown very large effect sizes, it may be most beneficial to rely on developmental positive behavioral change over time. Fourth, a moderately large group of girls were involved in delinquent behavior before middle school. Thus, preventive interventions that target "early starter" youth should include girls. Fifth, both studies that composed this project showed an overlap in status-public disorder offenses and alcohol use, suggesting the need for systematic assessment and treatment of substance use among delinquent girls. Sixth, it would be useful to conduct similar studies using official or arrest data, so that developmental patterns in arrest can be identified and the relationship between arrest and behavioral patterns can be explored. This project was based on research from two long-term longitudinal studies of delinquency with samples of girls. The studies are the Denver Youth Survey and the Fast Track Project. Researchers in these two studies cooperated in identifying common delinquency measures, conducting analyses, and integrating findings about the temporal ordering and patterning of girls' delinquent behavior. 10 tables, 6 figures,