Despite the prevalence of eugenics and determinist race-thinking during much of Steinbeck's working life, few critics have attempted to trace the echoes of that lineage in his work. Working within an interdiscplinary paradigm, I wish to argue that one of Steinbeck's oft-read and oft-analyzed novellas, Of Mice and Men, ought to be analyzed within the eugenic milieu of early twentieth-century America. Borrowing widely from intellectual history, philosophy, critical race theory, and labor studies, I present three distinct analytical channels for excavating the presence and activity of eugenic thinking in the novella. The first channel is a cosmological reading of the striking similarities between Steinbeck's non-teleological philosophy of "visceral understanding" and the worldview advanced by eugenicists–cum–political theorists Madison Grant and Lothrop Stoddard. The second is a micro-historical focus on California's role as a frontier for the institutionalization and practice of eugenics, a context that allows one to redefine some of Of Mice and Men's own narrative moments and structural relationships as marked by eugenic considerations and ethics. The third channel is a "geosophical" interpretation of the construction of the hobo archetype—which Lenny and George both fall under—in order to elucidate how hoboes and tramps become eugenically translated, a process of coding and identification of the unfit that signals to a coextensive precarity and revolutionary potential that "strange" and mobile persons embody within racially constituted spaces. In sum, much of my argument can be understood as turning around the effects and consequences of what would it mean to consider Of Mice and Men a eugenic novel in some sense.