Accompanied by nuggets of historical fascination such as the story of David Omand who was asked to translate an essay written in made-up Elvish and ended up as Director of GCHQ, or Jean Valentine, who volunteered in Dundee aged 18, disclosed that she loved the challenge of a cryptic crossword and found herself whisked down to Bletchley, these brain-teasing puzzles and riddles will give you a taste of what it felt like to be tested by the keenest minds in the country.