Abstract: In this essay, Mohamedou Ould Slahi reflects on how fifteen years of indefinite detention, torture, and abuse in the war on terror contributed to his development as a writer. He discusses the ways in which solitary confinement and other rules governing his captivity in a prison in Jordan and for fourteen years at Guantánamo forced him to keenly observe his surroundings and to conjure characters and stories from the smallest of details in his material life, from the most mundane interactions with guards, interrogators, and other prison personnel, and from dreams. Stitching these bits into narrative came about through listening to guards and other detainees tell their stories and from consuming approved television and film, often alongside the guards. For the author, writing both fiction and nonfiction provided an outlet for mental torment, but also created intense feelings of freedom, of imaginative life beyond cell walls. At the same time, he reflects on his role as a writer who survived Guantánamo as one of obligation to the memory of the many other young men who were disappeared and sometimes killed in the war on terror.