An impostor who claimed to be a refugee from Formosa (present-day Taiwan) named George Psalmanazar (1679?–1763) embodied two key aspects of addiction in eighteenth-century Europe: its connections to globalization and imperialism, and the complex interplay between the concept of “positive” addictions (such as addiction to study, devotion, or duty) and the growing attention paid to “negative” ones (addiction to superstition, sexuality, or intoxicating substances). Constantly changing his identity in response to his audience’s expectations, Psalmanazar lived a life of continual performance—performance that hinged on trading one set of addictions for another. As he abandoned his falsified persona as an opiate-addicted, sexually licentious Taiwanese aristocrat, Psalmanazar embraced a postimposture persona as a pious scholar of religion who, like the holy men he studied, was “addicted to the reading . . . [of] sacred writings.” Strikingly, however, this second life as a humble scholar was sustained by regular opiate use. What had changed was how Psalmanazar thought about his use of the drug: no longer in the service of “vanity” or “extravagance” but instead in the service of God. With their blend of introspection and self-deception, Psalmanazar’s Memoirs (1764) index the changing social and cultural roles of opiates and the concept of addiction in eighteenth-century Europe and beyond.