The Giant Book of Binary Puzzle: 1000 Hard to Extreme (12x12) Puzzles

Playing is not just a fun way to pass the time, due to its logical elements it has been found as a proven method of exercising and stimulating portions of your brain, training it even, if you will and just like training any other muscle regularly you can expect to see an improvement in cognitive functions. Some studies go as far as indicating regular puzzles can even help reduce the risk of Alzheimer's and other health problems in later life.