Overview: Tonight Mastermind reaches the semi-final stage when the first four of this year's first-round winners compete for a place in the final. In the splendid setting of the Nereid Room at the British Museum in London each contender must now take a specialised subject different from the one taken in the first round. Andrew Turek (solicitor) History of The Netherlands 1565-1715 Ivor Cooksey The physical geography of the USA and Canada Philip McDonald (schoolmaster) Life and work of James Brindley 1716-72 Albert Bertin (engineer and draughtsman) Life of Giuseppe Garibaldi and the Risorgimento