Mastermind, the BBC television contest, has subjected more than 1,400 would-be Brains of Britain to its rapid-fire interrogation. But after 25 years, the program was broadcast on television for the last time in September 1997. Its winners--taxi drivers, diplomats and teachers--became national celebrities and the program spawned an obsession with general knowledge, from Trivial Pursuit to pub quizzes. Its success has been due to a simple formula, the consistency of its standards and in large measure to the gravitas, courtesy, and humor of its Icelandic-born question-master, Magnus Magnusson. His book of behind-the-scenes or in-the-chair anecdotes is a valedictory celebration of a much-loved program.