This book project extended the work from Katy Park's article “Observation in the Margins, 500–1500,” which was commissioned for Lorraine Daston and Elizabeth Lunbeck, eds., Histories of Scientific Observation (Chicago: University of Chicago Press). In that piece, Katy Park argued that medieval writers understood experience (experientia/experimentum) and observation (observatio) as two distinct modes for producing natural knowledge using the senses. The former, which was native to the Aristotelian fields of natural philosophy and natural history, and by extension, medical theory, involved punctual sensory engagement with particular objects or events, while the latter, native to the Ptolemaic sciences of the stars, referred to the long-term accumulation of data concerning cyclical phenomena. Katy Park constructed a detailed account of observational and experiential practices as they developed over the course of the Middle Ages, establishing the role of sensory inquiry in a field often mischaracterized as entirely based on text. In the process, she argued for important continuities between early modern experimental practices and their medieval analogues.