Early modern culture was most fully expressed in events where materiality and textuality are inextricably intertwined: theatrical spectacles, royal parades, triumphal arches, processions, poetic tournaments, and jousts. At the other end of the spectrum, mainstream trends of nineteenth- and twentieth-century Hispanic philology—a prism through which early modern texts have been used and read for years—are part of a genealogy of thought that privileges form over matter. As a result, the radical importance of materials is frequently overlooked in the study of early modern culture. However, if we pay attention to early modern poetic and philosophical treatises, we can clearly notice the anxiety to justify the medium in which texts themselves were produced and transmitted. This article stresses the importance of materiality in two types of treatises from early modern Iberia: three sensory treatises by Oliva Sabuco (1587), Lorenzo Ortiz (1687), and Diego Calleja (1700); and three manuals of textual production by Juan del Encina (1496), Francisco Lucas (1580), and Alonso Víctor de Paredes (1680). The article sets out an argument for a materialist practice of literary criticism, a way to read early modern texts in terms of their own material theory.