The Little Book of Sudoku 4" contains over 200 brand new puzzles commissioned especially for this book & created by an expert in logic & artificial intelligence. The puzzles will test experts & train those unfamiliar with Sudoku helping to build your logic & reasoning skills improve your memory & keep your brain healthy & young by giving it a regular workout. The perfect companion for the work commute holidays & rainy afternoons " The Little Book of Sudoku Volume 4" will keep anyone's mind busy but beware as thousands of people have found it's highly addictive!"