Jon G. Allen is Chair in Mental Health Research and Professor of Psychiatry at the Menninger Department of Psychiatry and Behavioral Sciences at the Baylor College of Medicine, USA. He has written several books including Traumatic Relationships and Serious Mental Disorders for Wiley. For the past decade, he has worked closely with Peter Fonagy in the Menninger Child and Family Program, dedicated to research in attachment and developmental psychopathology. Peter Fonagy is Director of the Sub-Department of Clinical Health Psychology, University College London; and Adjunct Professor of Psychiatry, Menninger Department of Psychiatry and Behavioral Sciences at the Baylor College of Medicine. His ideas were central to developing mentalization as a concept, he has also catalyzed research and pioneered the application of mentalization to clinical practice.