Most leading global militaries, led by the United States, embrace military assistance as an essential tool for achieving their high-priority strategic objectives; yet, in spite of its prominence, military assistance activities are poorly informed by coherent strategy, nor are they rooted in underlying theoretical frameworks that help strategists understand and exploit causal mechanisms that can produce desired behaviors and outcomes. As a result, military assistance has struggled to consistently deliver positive, enduring results & and in some cases has proven strategically catastrophic. This book fills a gap in both academic literature and real-world practice: it identifies and elucidates several theoretical foundations of military assistance and offers four distinct strategic frameworks for designing military assistance initiatives. In so doing, the book will offer academics tools to better understand and evaluate military assistance and will offer practitioners a playbook for designing more effective military assistance interventions to address high-stakes global security dilemmas. Finally, it will propose an ethical framework for defense cooperation, offering much-needed guidance in an area fraught with moral risk.