Just a few years ago, people spoke of the US as a hyperpower—a titan stalking the world stage with more relative power than any empire in history. Yet as early as 1993, CIA director James Woolsey pointed out that although Western powers had “slain a large dragon” by defeating the Soviet Union in the Cold War, they now faced a “variety of poisonous snakes.”

In The Dragons and the Snakes, the eminent soldier-scholar David Kilcullen asks how, and what, opponents of the West have learned during the last quarter-century of conflict. Applying a combination of evolutionary theory and detailed field observation, he explains what happened to the “snakes”—non-state threats including terrorists and guerrillas—and the “dragons”—state-based competitors such as Russia and China. He explores how enemies learn under conditions of conflict, and examines how Western dominance over a very particular form of warfare since the Cold War has created a fitness landscape that forces adversaries to adapt in ways that present serious new challenges to America and its allies. Within the world’s contemporary conflict zones, Kilcullen argues, state and non-state threats have increasingly come to resemble each other, with states adopting non-state techniques and non-state actors now able to access levels of precision and lethal weapon systems once only available to governments.