This essay examines the role of Cesare Lombroso’s scientific and occult researches in shaping Yeats’s view of the mind, whether creative or criminal, in the mystical system of A Vision. Although the philosophical and aesthetic importance of Yeats’s mystical work has recently received serious attention, notably in W.B.Yeats’s A Vision: Explications and Contexts, the models used to recuperate and reassess this aspect of Yeats’s have not so far included minor contemporary figures like Lombroso, but have rather focused on classical, idealist, or political philosophy. Lombroso’s view of different human types, expressed most powerfully in his studies on genius and criminality, Criminal Man (1876) and The Man of Genius (1891), are important influences to consider for Yeats’s portrayal of representative psychological types in his typology of the phases of the Great Wheel. Beyond A Vision, Yeats’s reading of Lombroso connects with his interests in crime, eugenics, psychoanalysis, predestination, and the occult in his theater, for example, in his late play ‘Purgatory’, which is discussed in detail.