No matter how you look at it, the Ultimate Puzzle Challenge is big. In fact, it's enormous. There are more than 500 puzzles inside its covers, from cunning numerical conundrums and testing word games to logical teasers, enigmatic lateral thinking tests and abstract visual problems, and because they don't follow any special pattern, you'll never know what fiendish challenge is lying in wait for you over the page. They are collected into difficulty bands though, from the refreshingly straightforward to the downright devilish. You can get some practice in puzzle thinking with the easy section and build your mental muscles in the medium section, so that you'll have a fighting chance when it comes to the really hard part. You don't need any special skills or qualities to take on the Ultimate Puzzle Challenge, though: just a bit of common sense, some basic numeracy and literacy, the ability to think things through - and, of course, the stubborn willpower and determination not to be defeated by a mere puzzle.