This volume is a scholar’s edition of the first systematic American work on the philosophy of medicine, An Essay on the Philosophy of Medical Science (Philadelphia, 1844), by Elisha Bartlett (1804-1855). The book is divided into two parts: Part I consists of a critical introduction that gives a biographical sketch of Elisha Bartlett and situates his empiricist philosophy of medicine within the philosophical debates of the various theoretical schools of medical practice of early nineteenth-century America. Short summaries of Bartlett’s other writings and important addresses are presented, and many of the reviews of Bartlett’s work that appeared in the medical journals of his time are discussed. Also, the influence of the Paris clinical school on Bartlett’s philosophy is shown. Part II contains the Essay, and includes a previously unpublished manuscript of Bartlett’s philosophy of therapeutics, which develops some of the ideas of the Essay and adds another facet to Bartlett’s philosophy of medicine. In conclusion, some critical notes on Bartlett’s works are incorporated. A bibliography includes Bartlett’s published work, published reviews of his work, unpublished manuscripts and correspondence, and secondary literature on Bartlett and the philosophy of nineteenth-century medicine, and the book’s index provides scholars access to the major ideas in Bartlett’s work.