Did you know that Sudoku May Help Keep Your Brain 10 Years Younger? A study conducted by the International Journal of Geriatric Psychiatry (PROTECT study *) identified a close relationship between frequency of number-puzzle use and the quality of cognitive functions in adults over 50. In particular, the study also found that people who do puzzles regularly have brain function equivalent to 10 years younger than their age. These findings further contribute to the growing evidence that engaging in mentally stimulating activities could benefit the brain functionality. *https://pubmed.ncbi.nlm.nih.gov/30746778/ Challenge your mind and enjoy hours of fun with this standout and quality Sudoku book for adults. Over 1100 Sudoku puzzles across four difficulty levels Easy Medium Hard Super Hard Puzzles will Keep your mind roused and stimulated Large book - 8.5" x 11" with 243 white pages Skilfully generated with precise skill levels Solutions available to all puzzles Better quality white paper so pleasant to look at and write on Wide Margins so easy to fold book or tear the page out Makes a wonderful gift to family, friends or colleagues. Work puzzles alone or with your significant other for hours of fun and excitement. Keep your brain young, and have fun doing so.