The 21st Century Community Learning Centers initiative provides funds for afterschool programs across the country and is the only federal funding source dedicated exclusively to afterschool programming. 21st CCLC-funded programs operate during nonschool hours (i.e., before and after school, summers, holidays, and weekends) and present children with academic enrichment opportunities and other activities that support school-day learning and positive development. Programs with 21st CCLC funds also serve the families of participating children through services such as family literacy programs. "Research Update No. 4" focuses specifically on evaluations and research studies of programs that are funded by the 21st CCLC initiative, including both those programs that self-identify as 21st CCLC programs and also existing community- or school-based programs that use 21st CCLC funds in conjunction with other funding sources. It also provides an up-to-date bibliography of research studies and evaluations of 21st CCLC-funded programs in the Appendix. (Contains 6 endnotes.)