In the summer of 1968, The Beatles, at the height of their international fame following the release of Sgt. Pepper's Lonely Hearts Club Band the previous year, were in the middle of recording The White Album. Their age of innocence had passed. Political unrest was spreading and they were the global icons for a restless generation. In July that year they invited Don McCullin to spend a day photographing them. McCullin, the most hardened photographer in the world's war zones, had recently covered the bitter fighting during the Tet Offensive in Vietnam. He was astonished by the invitation. On Sunday 28 July he met The Beatles at the Sunday Times studio and photographed them in colour for a Life magazine cover. The day that followed has become known in Beatles lore as 'The Mad Day Out'. McCullin shot about fifteen rolls of film in his conspicuously dark style from Old Street to Limehouse and back at Paul McCartney's house in St. John's Wood. Though the existence of the photographs has been widely known, the pictures have until now remained largely unpublished. For a generation who lived through those years, the photographs are poignantly reminiscent of a vanished youth. For a younger generation, they represent a single day as a slice of history. The most striking image is a photograph, arranged by John Lennon, in which he posed as dead.