A strange and anonymous pamphlet was published in 1740 and the ensuing quest to determine its authorship has, several centuries later, given rise to an intriguing and fascinating series of events. This has unfolded through detailed and meticulous bibliophilic analyses that has generated heated and controversial debate about the identity of the author of the pamphlet. The protagonists in this intellectual adventure are two celebrated economists, John Maynard Keynes and Piero Sraffa, who both lived and taught in Cambridge and were united by a close intellectual relationship as well as a profound friendship. A further major protagonist is David Hume himself, who is discovered to have been the nameless author of the pamphlet. The reconstruction of this intriguing episode, put forward in this compact and highly readable book, offers the opportunity to revisit the original Introduction on which the two Cambridge economists placed their joint signatures. It was published by Cambridge University Press in 1938, in an edition that also featured the facsimile text of Hume?s short essay, which had lain in obscurity for almost 200 years. This pamphlet is now reproduced in The Enigma of the Treatise.