For nearly a decade Brett Velicovich was at the center of America's new warfare: using unmanned aerial vehicles--drones--to take down the world's deadliest terrorists across the globe. One of an elite handful in the entire military with the authority to select targets and issue death orders, he worked in concert with the full human and technological network of American intelligence--assets, analysts, spies, informants--and the military's elite operatives, to stalk, capture, and eliminate high value targets in al-Qaeda and ISIS