William Godwin’s Mandeville was described as his best novel by Percy Shelley, who sent a copy to Lord Byron, and it was immediately recognized by its other admirers as a work of unique power. Written one year after the battle of Waterloo and set in an earlier revolutionary period between the execution of Charles I and the Restoration, Mandeville is a novel of psychological warfare. The narrative begins with Mandeville’s rescue from the traumatic aftermath of the Ulster Rebellion of 1641 and proceeds through his early education by a fanatical Presbyterian minister to his persecution at Winchester school, his constant (and not unjustified) paranoia, and his confinement in an asylum. Mandeville’s final, desperate attempt to prevent his sister’s marriage to his enemy ends with his disfiguration, which also defaces endings based on settlement or reconciliation. The novel’s events have many resonances with Godwin’s own period. The historical appendices offer contemporary reviews, including Shelley’s letter to Godwin praising Mandeville, material explaining the novel’s complex historical background, and contemporary writings on war, madness, and trauma.