Wartime leaders should understand the link between violent means and political ends. They should also have a sense of how strategic decisions will affect the post-war peace. Yet they often fail to make these connections. Mistaking strategy for grand strategy, or misunderstanding the relationship between them, can frustrate soldiers and statesmen alike. Sometimes it can lead to national ruin. In this Adelphi book, Joshua Rovner offers a lucid analysis of strategy (a theory of victory) and grand strategy (a theory of security). He demonstrates vividly how these concepts interact in case studies from antiquity to the present, and he describes the implications for war and peace at a time of extraordinary technological change. Rovner’s work will prove indispensable to policymakers, scholars and anyone seeking to grasp these essential but often misunderstood concepts.