Also known as Sam Gwynne; Gwynne is a journalist whose work has been published in Time, Texas Monthly, New York Times, Harper's, and California Magazine. He co-authored his debut book, Outlaw Bank, with Jonathan Beaty. His second book, Empire of the Summer Moon: Quanah Parker and the Rise and Fall of the Comanches, the Most Powerful Indian Tribe in American History was published in 2010.