Diana Diamond, PhD, is Professor Emerita in the Doctoral Program in Clinical Psychology at the City University of New York and Senior Fellow at the Personality Disorders Institute at New York Presbyterian Hospital–Weill Cornell Medical College. She is also Adjunct Professor at the New School for Social Research and in New York University's Postdoctoral Program in Psychotherapy and Psychoanalysis. Dr. Diamond's primary interests are developing psychodynamic approaches to treating patients with personality disorders, and assessing changes in attachment, mentalization, and mental representation. Author or coauthor of numerous papers and several books, she is a recipient of the Research Award from Division 39 (Psychoanalysis) of the American Psychological Association. She serves on the editorial boards of Psychoanalytic Psychology and Psychoanalytic Inquiry, is Vice President of the Margaret Mahler Foundation, and has a private practice in New York City. Frank E. Yeomans, MD, PhD, is Clinical Associate Professor of Psychiatry at Weill Cornell Medical College, Director of Training at the Personality Disorders Institute at New York Presbyterian Hospital–Weill Cornell Medical College, and Adjunct Associate Clinical Professor of Psychiatry at the Columbia University Vagelos College of Physicians and Surgeons. Dr. Yeomans is an Honorary Member of the American Psychoanalytic Association, President of the International Society for Transference-Focused Psychotherapy, and Chair of the Committee on Psychotherapy of the Group for the Advancement of Psychiatry. His primary interests are the development, investigation, teaching, and practice of psychotherapy for personality disorders. He has helped establish training programs in many countries and has published numerous articles and books. Barry L. Stern, PhD, is Clinical Associate Professor of Psychology in Psychiatry at the Columbia University Vagelos College of Physicians and Surgeons and a faculty member at the Columbia University Center for Psychoanalytic Training and Research. Dr. Stern’s work centers on the study of personality and mental health and the application of transference-focused psychotherapy with patients across the spectrum of personality functioning, and with couples. Dr. Stern has been a lead investigator in the validation studies of the Structured Interview of Personality Organization (STIPO) and its revision (STIPO-R). His published empirical work focuses on the STIPO and the structural assessment of personality. He has a private practice in New York City. Otto F. Kernberg, MD, is Professor of Psychiatry and Director of the Personality Disorders Institute at New York Presbyterian Hospital–Weill Cornell Medical College, Training and Supervising Analyst at the Columbia University Center for Psychoanalytic Training and Research, and Distinguished Visiting Professor of Psychiatry at the Albert Einstein College of Medicine. Dr. Kernberg is an Honorary Member of many international psychoanalytic institutes, past president of the International Psychoanalytic Association, and Distinguished Life Fellow of the American Psychiatric Association (APA). He is a recipient of the Distinguished Service Award from the APA, the first Sigourney Award for Distinguished Contributions to Psychoanalysis, the Edward A. Strecker Award from the Institute of Pennsylvania Hospital, and the Heinz Hartmann Award from the New York Psychoanalytic Institute, among other honors. Dr. Kernberg has conducted research and published seminal books and articles on psychoanalytic psychotherapy, psychoanalytic object relations theory, and severe personality disorders.