Much of our knowledge about PTSD is based on studies of adults. As evidenced by the birth of new scientific disciplines (e.g., developmental translational neuroscience), it is clear that what we learn from research involving adults may not necessarily be applicable to children and adolescents. Indeed, the field of child and adolescent PTSD and trauma is relatively young, although the knowledge base has increased substantially over the past 2 decades. Moreover, task force members recognize that mental health professionals may have many different perspectives on child and adolescent trauma, particularly in regard to the specific nature of its effects and what interventions may be most effective in reducing negative outcomes and enhancing adaptive functioning. Although we attempt to summarize here what is currently known about child and adolescent PTSD and trauma, we welcome ongoing discussion and novel perspectives, which help to advance the field.