Early British medical libraries owned by practitioners of medicine are not easily distinguished from those owned by persons with a purely theoretical interest in medicine. This is not just a function of our ignorance about the owners of these books – although it is true that we may not know enough to characterise them – but reflects the difficulty of drawing hard and fast lines between theory and practice of medicine. Almost all of the men who can be identified as possessing medical degrees from Oxford, Cambridge and the Scottish or other European universities are known to have practised as well as taught medicine. Conversely, those book-owners we can identify as surgeons or unlicensed medical practitioners did not keep in their libraries books which were of a kind noticeably different from those owned by the university trained men. Both licensed and unlicensed practitioners might own recipe-books, or herbals, or texts on surgery and the medical practica. So too with institutions, monastic houses, colleges or gilds of practitioners – they often seem to have owned medical books that reflected both the curriculum of the university medical school and the exigencies of medical treatment of patients.

The most important distinctions that can be drawn in respect of medical libraries are linguistic. Some owners had only books that were in English, in Gaelic or in Welsh. The overwhelming majority of medical libraries in the early period, however, were made up wholly of books in Latin. If other languages were represented in these Latin-dominated libraries, they were French, Italian or German books, rather than English.