The purpose of this article is to provide a brief overview of how clinical psychology evolved in the United States as a prelude to discussing the emergence of psychological clinical science in the closing years of the 20th century. Despite the growth of clinical psychology, mental disorders remain highly prevalent, compelling us to envision new ways to deliver services in an effective but efficient manner. Topics include the dissemination gap, the affordable access gap, and the Psychological Clinical Science Accreditation System (PCSAS). Examples of novel methods for addressing the problem of public mental health in the 21st century are discussed. Finally, I close by considering the potential relevance of our experience in America for European clinical psychology.