Mark Greaney has a degree in international relations and political science. In his research for the Gray Man novels, including Agent in Place, Gunmetal Gray, Back Blast, Dead Eye, Ballistic, On Target, and The Gray Man, he traveled to more than fifteen countries and trained alongside military and law enforcement in the use of firearms, battlefield medicine, and close-range combative tactics. He is also the author of the New York Times bestsellers Tom Clancy Support and Defend, Tom Clancy Full Force and Effect, Tom Clancy Commander in Chief, and Tom Clancy True Faith and Allegiance. With Tom Clancy, he coauthored Locked On, Threat Vector, and Command Authority.

Lt. Col. Hunter "Rip" Rawlings IV is an active duty Marine and a  veteran of combat in Afghanistan and Iraq. A former infantry battalion commander and light armored reconnaissance officer, he has served for more than twenty years. He is currently assigned to Quantico as the Warfighting Director for Marine Corps Command and Staff College. In his spare time, Lt. Col. Rawlings is an avid scuba diver, small-craft sailor, and microbrewer.