James Hogg's Private Memoirs and Confessions of a Justified Sinner (1824) is a novel whose complex religious contexts have often baffled readers. The novel satirizes an extreme—and totally unrepresentative—form of Scottish Calvinism. Those critics who have been interested in situating the novel within this theological and cultural background have too often adopted a myopic reading that limits the influence of Scottish Calvinism to broadly soteriological themes: predestination, election, justification and antinomianism. By contrast, this essay argues that Hogg's debt to Scottish Calvinism went much further than these soteriological categories, for Scottish Calvinism also provided Hogg with the staple elements of his novel's demonology. A fascination with demons was typical of standard descriptions of Scotland's “worlds of wonder” in the late seventeenth and eighteenth centuries, and the demon that haunts the Justified Sinner emerges from and visibly reflects these earlier traditions of the Presbyterian occult. But this essay also argues that Scottish writers' interest in demonology is not inextricably linked to its background in the popular culture of early modern Calvinism. From the late nineteenth century to the present day, Scottish writers have continued to invoke themes from this earlier demonology to describe overt evil in the modern secular world.