Without access to detailed information about the specific content and approach of pre-packaged SEL programs, few schools and OST organizations are able to use data to aid them in selecting and implementing SEL programming, and they struggle to select and use programs that are best suited to their contexts and the specific challenges they face. There is thus a need for resources that comprehensively describe program content in a way that enables schools, OST organizations, and other practitioners tasked with developing young people's social and emotional skills to see inside programs in order to make informed decisions about SEL programs or strategies. This report addresses that need by looking inside 25 leading SEL and character education programs to identify and summarize key features and attributes of SEL programming for elementary-age children. Schools and OST organizations vary widely in their missions, structures, pedagogies, and target populations, as do SEL programs. The goal of this report is to provide schools and OST organizations with detailed information about the specific curricular content and programmatic features of each program in a way that enables them to look across varying approaches and make informed choices about the type of SEL programming that is best suited to their particular context and needs. (author abstract)