“An Eco-Alchemical Vision: Hermetic Writing in Twentieth-Century British Literature” examines the intersection of alchemical thinking with contemporary green discourses. This project focuses on four writers from the last century: W. B. Yeats, Charles Williams, Lindsay Clarke, and Patrick Harpur. It considers a wide selection of their writing across literary genres, including the novel, the short story, the essay and poetry. While each of the texts under consideration figures the relationship between the human and the nonhuman world in different ways, reading them alongside one another reveals a shared preoccupation with the status of the material world. For these writers, the alchemical tradition offers a way of both speaking and thinking about physical phenomena that affirms our complex entanglement with materiality. Like the medieval and Renaissance alchemists, all four writers seek to disrupt the rigidity of the boundaries often erected between what dominant modes of thinking in the Western philosophic tradition have categorized as organic and inorganic. My analysis of each writer will draw out how the material is represented in their literary work, and what we might gain from reading their work ecocritically. There are thus three converging lines of inquiry that will frame this project: first, how does this minor current of what I am describing as “eco-alchemical” fiction and poetry fit within larger movements in twentieth-century British literature; second, how do these four figures recuperate alchemical thinking for twentieth-century and contemporary audiences; and third, what does this contribute to the current field of ecocriticism.