Writing with the Grain explores moments of dynamic conceptual and formal exchange between poetic and environmental worlds in late-medieval vernacular literature. It traces the ways that late medieval poets envisioned the environment as a participant in the production of poetry—a view which challenges the notion that, in creative expression, humans “give form” to things, as if matter were brute, subordinate, passively awaiting the agent who shapes it (often called “hylomorphic” theories of creative expression). Examining poets like Chaucer and Gower, I argue for a view of late-medieval poetic production that seeks to “follow the grain” of the material world, so to speak, embracing the material fluctuations of the environment and allowing these fluctuations to participate in the shaping of poetry. Writing with the Grain argues that late-medieval vernacular writers understood that our environmental contexts–in all their materiality–have striking consequences for how we understand poetic form. Drawing on phenomenological understandings of creativity, Chapter One reads Robert Henryson’s Testament of Cresseid alongside Chaucer’s Canterbury Tales to argue for a view of poetic production characterized by human-environmental correspondences, where poets follow forms that are latent in the environment itself. In Chapter Two, I explore the conceptual and physical connections between poetic and environmental matter. I argue that Chaucer’s House of Fame, with its attention to concepts of movement and proliferation, puts forth a view that sees creativity born within the whirl of the Aristotelian world of fluctuation. In Chapters Three and Four, I demonstrate the ways medieval poets like John Gower and John Lydgate used literary form to enact environmental form, from the role of poetic form in structuring environmental concepts such as climate and pollution, to the use of fiction and dialogue in capturing our skillful engagements with material objects such as tools.