Prove your logical and arithmetical prowess by solving the exceptionally tricky problems in Mensa's Most Difficult Number Puzzles.

This full-colour book features a huge variety of numerical conundrums that are certain to test even the most adept of puzzlers. Some puzzles – such as sum skyscraper and calcudoku – will test your mental maths, while others – such as touchy and bridges – will provide a trial for your logical and lateral thinking. Are you up to the fiendish challenge?

Dr Gareth Moore is the author of over 250 bestselling international puzzle and brain-training titles from a wide range of publishers. His books are available in over 40 countries, with worldwide sales of over 5 million copies. His puzzles also appear in magazines and newspapers, and can be played online at the PuzzleMix website. He is also the creator of Brained Up, a cutting-edge brain training site that offers daily sessions to help you make the most of your brain, and is a director of the UK Puzzle Association as well as a former board member of the World Puzzle Federation. He works with a co-writer, Laura Jayne Ayres, on his murder mystery-themed puzzle books.