Of the Presocratic thinkers traditionally credited with the foundation of Greek philosophy, Xenophanes, Parmenides and Empedocles are exceptional for writing in verse. This is the first book-length, literary-critical study of their work. It locates the surviving fragments in their performative and wider cultural contexts, applying intertextual and intratextual analyses in order to reconstruct the significance and impact they conveyed for ancient audiences and readers. Building on insights from literary theory and the philosophy of literature, the book sheds new light on these authors' philosophical projects and enriches our appreciation of their works as literary artefacts. It also expands our knowledge of the genres in which they wrote, of the literary culture of the Western Greek world, and of the development of Greek poetics from the Archaic to the Classical periods, exposing the influence of these thinkers on more famous Sophistic and Platonic ideas about literature.