Recent advances in the scientific understanding of the human mind and brain along with the emphases on evidence-based practice and competency-based education are creating increasing pressures to update some of the traditional approaches to structuring and organizing education and practice in the field. There have also been many calls in recent years for a unified approach to conceptualizing professional practice in psychology. This book examines whether there exists a unified conceptual framework for the field that is firmly based on current scientific understanding regarding human development and functioning, that applies across all the clinical populations and practice areas within the field, and that would also help integrate professional psychology more fully into health care and the sciences generally.