Cult of the Will is the first comprehensive study of modernity’s preoccupation with willpower. From Nietzsche’s “will to power” to the fantasy of a “triumph of the will” under Nazism, the will—its pathologies and potential cures—was a topic of urgent debates in European modernity. In this study, Michael Cowan examines the emergence of “will therapy” and its impact on arts and culture in Germany after 1900. The book’s five chapters lead readers through cross sections of modern German cultural history, including not only literature and aesthetics but also medicine, economics, body culture, and pedagogy. Modernity’s fixation on willpower helped prepare the way for fascism, but this trajectory is not Cowan’s main concern. His focus falls rather on more widespread “technologies of the self” and their role in the effort to reimagine agency for a modern subject caught up in increasingly complex systemic networks.