This issue of Psychiatric Clinics of North America, edited by Drs. Frank Yeomans and Kenneth Levy, will offer a comprehensive review of key topics of importance in the study of Borderline Personality Disorder. The series is led by our Consulting Editor, Dr. Harsh Trivedi of Sheppard Pratt Health System. This issue will explore the following topics: Conceptual models, Diagnosis and assessment, Differential diagnosis, Community and Clinical Epidemiology, Comorbidity, Longitudinal Course, Neuroscience and social cognition, Attachment, Psychotherapy and medication treatment research, Psychotherapy with children and adolescents, and Family and patient perspectives, among others.