SNOWis the codename assigned to Arthur Owens, the most important  British double agent in the early years of the Second World War. Described by Mi5 as a typical underfedCardiff he type became the first of the great double-cross agents who  were to play a major part in Britain's victory over the Germans. When  the stakes could not have been higher, MI5 sought to build a double-cross system based on the shifting loyalties of a duplicitous, philandering and vain anti-hero who was boastful and brave, reckless andcalculating, ruthless and mercenary... but patriotic. Or was he?Based on hundreds of secret Mi5 files, meticulous research and for the first  time, the testimony of his family. Snow reveals the truth about an  extraordinary man whose messages were used to make the first break  through in the german Enigma codes at Bletchley Park and whose daughter went on to become a Hollywood film star.