He was the son of a hereditary peer, one of the wealthiest men in Britain. At the age of 21 he founded The Film Society, and became a pioneering standard-bearer for film as art. He was a collaborator of Hitchcock, rescuing The Lodger and later producing his groundbreaking British thrillers The Man Who Knew Too Much, The 39 Steps, Secret Agent and Sabotage. He directed comedies from stories by H.G. Wells, worked in Hollywood with Eisenstein, and made documentaries in Spain during the Civil War. He lobbied for Trotsky to be granted asylum in the UK, and became a leading propagandist for the anti-fascist and Communist cause. Under constant MI5 surveillance, he became a secret agent of the Comintern and a Soviet spy. This is the remarkable story of Ivor Montagu, and of the burgeoning cinematic culture and left-wing politics of Britain between the wars.