The 526-page report, Preventing Mental, Emotional, and Behavioral Disorders Among Young People: Progress and Possibilities, updates the landmark 1994 IOM report on prevention, Reducing Risks for Mental Disorders, which focused on the entire life span. In the past 15 years, research has shown that half of all lifetime psychiatric disorders begin before age 14 and three-fourths begin by age 25, and research on risk factors among children and adolescents has burgeoned. The authors of the new report, which cites more than 1,500 references and includes an appendix listing 45 meta-analyses, were tasked with reviewing this large body of research, as well as findings from prevention intervention research, developmental neuroscience, cost-benefit analyses, and implementation-dissemination studies. The report describes methodological advances in prevention research and outlines key components of a prevention infrastructure.