Overview: In tonight's fourth semi-final are David Steele (local government accountant) on the life and career of President Truman; Paul Webbewood (civil servant) on the life and career of Oliver Cromwell , 1599-1658; Dave Ross (welfare rights worker) on European political history, 1870-1945; Bernard Howell (civil servant) on the novels of William Golding. With Magnus Magnusson at the University of Essex, Colchester.