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 bestselling 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. Mensa is the largest and oldest high IQ society in the world. It is a non-profit organization open to people who score at the 98th percentile or higher on a standardized, supervised IQ or other approved intelligence test.