Gideon's Spies: The Secret History of the Mossad is a 1999 book by Welsh author Gordon Thomas on the Mossad, the Israeli intelligence service. Two years previously Thomas wrote and narrated a major documentary for Channel Four - The Spy Machine - co-produced by Open Media and Israfilm. As Thomas's "Notes on Sources" afterword to Gideon's Spies makes clear, the research for the film provided him with some, but not all, of the sources and material he used when writing his later book independently of Channel 4 and the film-makers. Gideon's Spies has so far been published in 16 languages.