A brief, practical guide to the most current research on and treatment for borderline personality disorder (BPD). Borderline personality disorder (BPD) is associated with severe emotion dysregulation, widespread impulsivity, and highly unstable interpersonal relationships. BPD patients often threaten suicide, make attempts, or suffer from chronic suicidal ideation. The disorder is difficult to diagnose because it is complex, straddles multiple domains and often appears alongside several comorbidities. For all these reasons it is exceedingly difficult to treat, and presents a major challenge for mental health providers. In this updated, practical and evidence-based guide, author Joel Paris uses the biopsychosocial model to contextualize and inform diagnosis and treatment for BPD. Chapters describe risk factors associated with BPD, the development of BPD across the lifespan, and how BPD can be managed in therapy. While dialectical behavior therapy (DBT), is the most often studied therapeutic approach with this population, common factors in all approaches can be utilized to help patients regulate emotions, reduce impulsivity, and improve their interpersonal skills. Common challenges such as the length, expense, and general accessibility of treatment are examined in detail, as is as the risk of suicidality.