The most momentous change in American warfare over the past decade has taken place away from the battlefields of Afghanistan and Iraq, in the corners of the world where large armies can’t go. The Way of the Knife is the untold story of that shadow war: a campaign that has blurred the lines between soldiers and spies and lowered the bar for waging war across the globe. America has pursued its enemies with killer drones and special operations troops; trained privateers for assassination missions and used them to set up clandestine spying networks; and relied on mercurial dictators, untrustworthy foreign intelligence services, and proxy armies.

This new approach to war has been embraced by Washington as a lower risk, lower cost alternative to the messy wars of occupation and has been championed as a clean and surgical way of conflict. But the knife has created enemies just as it has killed them. It has fomented resentments among allies, fueled instability, and created new weapons unbound by the normal rules of accountability during wartime.