In the first half of the eleventh century, a close-knit group of scholars in southwest India did something new. They began composing texts about practical topics in a register of language they called “New Kannada.” Using this new register they compiled recipes, solved bureaucratic mathematical problems, predicted the weather, and waxed poetic about caring for animals and locating underground water. This dissertation explicates this turn to vernacular sciences and its epistemic consequences in South Asia. New vernacular sciences represented a tectonic shift in the systematics of knowledge in South Asia, but transregional languages did not disappear. Scholars writing in vernacular languages were implicated in larger networks of transregional scholars. In this mixed intellectual environment, authors writing in Sanskrit and Kannada disputed and redefined the meaning of scholarship, debating the value of erudition and experience. This dissertation follows a series of controversies carried out in Sanskrit and vernacular languages in precolonial South Asia. By focusing on controversies, the dissertation tells a “big-enough” history of science that neither culminates in a story of a civilization nor remains limited to case studies. Chapter one opens the dissertation by posing the question: What did it mean to be a scholar? It follows the career of Bilhaṇa, an itinerate Kashmiri intellectual who travelled across the subcontinent and eventually found steady employment in the court of the Western Cāḷukyas in southwest India. Working outwards from this single individual, the chapter charts changing norms of authorship that came along with new models of court funding and changing rules for scholastic dispute. Chapter two asks the question: Who was an authority? The chapter focuses on disputes over medicine and the value of the medical classics broached in the Rāṣṭrakūṭa court. Chapter three asks the two related questions: What was the value of the everyday? And what was the importance of vision in medieval India? It focuses on two Jain scholars named Vādirāja and Prabhācandra, who worked on related epistemological projects in the Western Cāḷukya and Paramāra courts. Chapter for follows how these philosophers investigated the distinction between nature and convention by contesting the reality of caste. Chapter five turns to scholars writing in the Western Cāḷukya court, who composed scholarly texts in vernacular languages. It asks the question: What were the languages of scholarship? The chapter describes the writings of a group of scholars who authored manuals on astrology, medicine, toxicology, mathematics, politics, and erotics. The chapter argues that these scholars invoked both erudition and experience as they composed texts they called “worldly sciences” that were “useful to the people of the world.” Chapter six asks the question: What was local knowledge? The chapter argues that authors writing in Sanskrit and Kannada developed a new set of agricultural sciences around weather prediction, reservoir and well construction, and horticulture. Chapter seven concludes the dissertation by showing how these medieval sciences were put to new uses in the early modern period. It tells a history of scholarly practices of information management on the eve of colonialism.