Diana Preston studied modern history at Oxford University. Her new book, 'Lusitania: An Epic Tragedy', describes a pivotal event in the First World War, the sinking of the Cunard luxury liner by a German submarine in 1915 with the loss of some 1200 lives. Diana's research on the 'Lusitania' took her from the National Archives in Maryland, to British official records in the UK, to little-known German military archives where she found incriminating new material, to wading into the Irish Sea at the same time of year that the 'Lusitania' sank and to standing in the damp conning tower of the submarine that torpedoed her.