This article examines Pynchon’s literary invention of Deleuze and Guattari’s Italian Wedding Fake Book. Featured in his novel Vineland ( 1990), previous scholarship has either dismissed the reference as a throwaway joke or argued that Pynchon’s invocation of the philosophers is intended to point us towards the author’s engagement with Anti-Oedipus (1972). Following Charles Hollander’s argument that Pynchon’s jokes indicate important themes in his texts, this article looks beyond the reference to Deleuze and Guattari and to the author’s alignment of these philosophers with a “fake book”. A fake book is a book of basic chords, lyrics, and/or melody lines, which allows those who can read sheet music to improvise, or “fake”, the performance of compositions. Given that it is Deleuze and Guattari’s second collaboration of A Thousand Plateaus (1980) that addresses musicality in various guises, I focus on how Pynchon engages with the concepts of this latter text in terms of improvisation, social organisation, and assemblage. This engagement, I suggest, is less about influence that it is about identification. This is to say that Pynchon has long shared the philosophical outlook of Deleuze and Guattari, as demonstrated with reference to his short story “Entropy” (1960).