In recent history, planned violent attacks have persisted in the United States and abroad. Ranging from targeted attacks on private individuals, public figures, schools, universities, corporations, and public venues, among others, these attacks have continued to illustrate the need for improved threat assessment and management efforts at local and national levels. In the few years since its publication in 2014, the International Handbook of Threat Assessment has become the gold standard textbook for the prevention of targeted violence. With this new edition, editors J. Reid Meloy and Jens Hoffmann have expanded their landmark text, reflecting the rise of scholarship and growth within the field of threat assessment and management. The book spans across disciplines and explores the foundations of threat assessment, the fields of practice in which it is utilized, and provides detail on practical applications from the most notable threat assessors and programs in North America, Europe, and Australia. Since the first edition, new chapters focusing on lone actor terrorism, insider threats, cyberthreats, the use of artificial intelligence, bystander effects, and enhanced interviewing techniques, offer new guidance for threat assessment professionals. International Handbook of Threat Assessment is the comprehensive resource for mental health practitioners, law enforcement, and professionals working to prevent targeted violence. This guide will serve as inspiration for further research and equip those working to intercept harm with the necessary tools for intervention.