The specific methods used to construct Enlightenment systems of natural history have proven to be the bete noir of studies that address eighteenth-century culture. One of the reasons that systematic classification has received so little attention can be attributed to the fact that natural history was an extremely diverse subject that appealed to a wide range of practitioners; from wealthy patrons to professionals and educators. In order to show how the classification practices of a defined institutional setting enabled naturalists to create systems of natural history, this book focuses on developments at the Medical School of the University of Edinburgh and in particular the teaching of one of Scotland's most influential Enlightenment naturalists, Dr John Walker, who was the professor of natural history at the medical school from 1779-1803. The first half of the book traces Walker's early career to find out how a naturalist became a naturalist during the Enlightenment.Walker did not live in a chemical vacuum and there was more to his life than the analytic processes of chemistry. He was a traveller, cleric, author and advisor to extremely powerful aristocratic and government patrons, and his primary concern was the usability of any system and the way in which it allowed for improvements, therefore as well as showing how naturalists were taught systematics this section also highlights the institutional and social context that fostered their careers. The second half of this book looks at how the language of Enlightenment natural history drew from a large and multifaceted canon of texts, and not just the standard canon of Linnaeus' "Systema Naturae" and Buffon's "Histoire Naturelle". We trace this language of natural history from chemistry, to mineralogy and geology, and finally into Walker's own lecture notes and his own revisions of classification methods, which were then passed on to his students.As many of Walker's students would go on to become influential industrialists, scientists, physicians and politicians, this book therefore also provides a unique insight into how many of Britain's leading Regency and Victorian intellectuals were taught to think about the composition and structure of the material world. By explicitly connecting eighteenth-century geology to the chemistry being taught in medical settings, this book offers a new interpretation of the nascent earth sciences as they were practiced in Enlightenment Britain.