This article proposes that Jonas’s understanding of gnosticism differs substantially from the account typically associated with him. That standard account takes the basic tenets of existentialism as the foundation to its discussion of alienated individuality, whereas Jonas’s system uses neo-Kantian epistemology to construct both alienation and individuality out of a unified field of human interaction. Within his framework, gnosticism is a single historical-philosophical episode of inauthenticity, highly influential yet isolated in time, unlike the ubiquitous understanding of it. This article reviews Jonas’s system, elements of its early and later acceptance, along with selected issues raised by critics, from Heidegger and Scholem to Colpe, Yamauchi, Williams, and King.