Agent of Empire is a detailed study of creative works inspired by the escapades of the American soldier of fortune William Walker. The leader of several fractious, bloody forays into Mexico and Central America in the 1850s, Walker was executed in 1860 by a Honduran firing squad. Brady Harrison looks at a dozen works, such as Bret Harte's novel The Crusade of Excelsior (1887) and Alex Cox's film Walker (1987), to show how Walker's life and legacy have been explored in journalism, poetry, fiction, drama, and cinema for over a century. At the heart of our ongoing interest in Walker, says Harrison, is the need to understand the ever-shifting ambitions and arguments that have driven American economic, military, and paramilitary ventures around the globe over the past 150 years. Harrison discusses how the mercenary romance, an understudied subgenre of the historical romance first popularized by Bret Harte and Richard Harding Davis, owes its conception to William Walker. Engaging the work of other scholars such as Quentin Anderson and Judith Butler, Harrison places Walker in the company of Aaron Burr, Theodore Roosevelt, Oliver North, and other American conquistadors.