This chapter provides an overview of Mailer’s fixation on criminality, and the duality and complexity he often found in criminal figures. This fascination is most apparent in his treatments of Gary Gilmore and Lee Harvey Oswald, and in his support for Jack Abbott, the contexts for which are discussed here. In 1975, Mailer published his Pulitzer Prize-winning work The Executioner’s Song, which probed the depths of Gary Gilmore’s psyche, examined the individuals and environment that helped to shape him, and recounted the media circus that followed his much publicized trial. While working on the novel, Mailer began corresponding with convicted criminal Jack Abbott and, intrigued by Abbott’s intellectual and creative sides, vouched for Abbott’s parole request in 1981, which was granted with tragic consequences, when Abbott murdered a waiter shortly after his release. In the 1990s, Mailer published Oswald’s Tale, a literary biography that also reveals Mailer’s fixation on the psychology and dual eccentricities and banalities of the criminal.