This crucial match, which comes from the Bute Hall in Glasgow University, will establish which of tonight's four contenders will move forward to the final round. The contenders are:
Richard Green (zoo keeper): History of the Isle of Man
John McLeod (local government officer): Sir Arthur Sullivan and his Contemporary Composers John Old (teacher): The Texan Revolution 1835-1836 Peter Owen (chartered surveyor): Life and Works of Beatrix Potter