A colorful collection of the most difficult Logic based puzzles on the market, compiled by Mensa puzzle setters.

Dr Gareth Moore is one of the world's leading puzzle-setters, with more than 750,000 book sales to his name. He is the author of more than 75 international brain-training titles including the best-selling puzzle book The Ordnance Survey Puzzle Book, which has sold more than 120,000 copies in the UK. He is also the creator of Brained Up, a cutting-edge brain training site offering scientifically designed daily sessions to help you make the most of your brain.