This book offers readers comprehensive, empirically grounded knowledge regarding suicidality. It provides a strong foundation for mental health professionals and students who may encounter and work with suicidal clients and those interested in this area. The book is divided into twenty one chapters across seven parts. The introductory part focuses on how societal and individual ethics, philosophies, cultures, ethnicities, and religions relate to suicidal behavior and how they inform clinical practice and treatment. Part II, "Suicidality Across the Life Span", explores suicidality among children and adolescents, adults, and older adults. The nature, risk, and protective factors of suicidality differ among the various stages of life. Part III, "Suicide and Mental Illness", centers on suicide across three high-risk diagnostic categories and focuses specifically on mood disorders, psychotic disorders, substance disorders, and personality disorders. Part IV, "At-Risk Populations", highlights several vulnerable groups such as active military personnel and veterans; Lesbian, Gay, Bisexual, Transgender, and Queer/Questioning (LGBTQ) population; and the homeless, Native Americans, and incarcerated individuals. Part V, "Assessing Suicide", presents core guidelines and key components of assessing suicide risk. Part VI, "Evidence-Based Treatments", focuses on empirically supported, evidence-based psychosocial practices. It presents five widely used psychosocial evidence-based treatments for suicidality such as crisis intervention, cognitive behavioral therapy, dialectical behavioral therapy, interpersonal psychotherapy, and motivational interviewing. The final part, Surviving Suicide, examines family and friend survivors of suicide with a special focus on the grief process and approaches to working with family. It also examines the impact of client suicide on treating clinicians. Each chapter begins with a clear set of goals and objectives, followed by individual exercises, small group exercises, case examples, role plays, a closer look, key points, electronic resources, and knowledge acquisition tests.