In this issue Psychiatric Services continues its series on evidence-based practices with two articles. In the first article, Kimberly Hoagwood, Ph.D., and her colleagues summarize the literature on evidence-based practice in children's mental health services. They caution that the evidence base for children's services is relatively new and that large-scale efforts to disseminate validated treatments for children should await further research on how these treatments fit into real-world practice settings (see page 1179). In the second article, Sonja K. Schoenwald, Ph.D., and Dr. Hoagwood discuss the growing literature on the diffusion of innovations, such as in agriculture and technology, and describe how knowledge gained from those studies can inform efforts to incorporate efficacious treatments into usual-care settings (see page 1190). Robert E. Drake, M.D., Ph.D., and Howard H. Goldman, M.D., Ph.D., are editors of the evidence-based practice series.