Identifying key hermetic moments in Deleuze's thought, including his theories of art, subjectivity, and immanence, Ramey argues that the philosopher's work represents a kind of contemporary hermeticism, a consistent experiment in unifying thought and affect, percept and concept, and mind and nature in order to engender new relations between knowledge, power, and desire. By uncovering and clarifying the hermetic strand in Deleuze's work, Ramey offers both a new interpretation of Deleuze, particularly his insistence that the development of thought demands a spiritual ordeal, and a framework for retrieving the pre-Kantian paradigm of philosophy as spiritual practice.