"Product Features: 1. 400 Medium to Hard puzzles for adults provides plenty of fun for adults. 2. The handy pocket size of the book would allow you to take it with you where you go. 3. No mistakes! Checked for errors manually. 4. All of the puzzles are large enough to be comfortably completed. It is aimed toward the advanced players and can make us smarter.This stylish collection of 400 nice puzzles for adults ranging in difficulty from Medium to Hard will keep you entertained for hours while boosting your memory and cognitive skills. Indulge yourself with hours of fun and keep your mind healthy and active with our cool puzzles set for adults! The 8 by 8 Sudoku puzzle is played exactly the same way as the standard Sudoku- you have to put the numbers so that they appear only once in each row, column, or block. 8 by 8 Sudoku new puzzles for adults are easier than standard 9 by 9. Start with 8 by 8 grids then move up to regular 9 by 9. Keep your brain sharp and improve your concentration with a puzzle a day! This big Sudoku book has everything you need to stimulate your mind. Grab a pencil and start flexing your mind today! Enjoy hours and hours of fun Sudoku solving with our great logic puzzles for adults! "