This book analyzes the evolution of Russian military thought and how Russia's current thinking about war is reflected in recent crises. While other books describe current Russian practice, Oscar Jonsson provides the long view to show how Russian military strategic thinking has developed from the Bolshevik Revolution to the present. He closely examines Russian primary sources including security doctrines and the writings and statements of Russian military theorists and political elites. What Jonsson reveals is that Russia's conception of the very nature of war is now changing, as Russian elites see information warfare and political subversion as the most important ways to conduct contemporary war. Since information warfare and political subversion are below the traditional threshold of armed violence, this has blurred the boundaries between war and peace. Jonsson also finds that Russian leaders have, particularly since 2011/12, considered themselves to be at war with the United States and its allies, albeit with non-violent means. This book provides much needed context and analysis to be able to understand recent Russian interventions in Crimea and eastern Ukraine, how to deter Russia on the eastern borders of NATO, and how the West must also learn to avoid inadvertent escalation.