Long-time art critic Richard Dorment reveals the corruption and lies of the art world and its mystifying authentication process. Late one afternoon in the winter of 2003, art critic Richard Dorment answered a telephone call from a stranger. The caller was Joe Simon, an American film producer and art collector. He was ringing at the suggestion of David Hockney, his neighbour in Malibu. A committee of experts called the Andy Warhol Art...