Two medical essays in the hand of John Locke survive amongst the Shaftesbury Papers in the National Archives (National Archives PRO 30/24/47/2, ff. 31r–38v and ff. 49r–56r). Since the 1960s their authorship has been disputed. Some scholars have attributed them to the London physician Thomas Sydenham, others have attributed them to Locke. Detailed analyses of their contents and the context of their composition provide very strong evidence for Lockean authorship. This is reinforced by the application of the most recent techniques of computational stylistics.