** ENJOY THE MOST POPULAR PUZZLE GAME IN THE WORLD! WHETHER YOU WANT TO KEEP YOUR BRAIN YOUNG AND ACTIVE, DEVELOP LOGICAL THINKING OR JUST KEEP YOURSELF BUSY TO AVOID BOREDOM... THIS BOOK WILL HELP YOU WITH ITS UNIQUE SUDOKU PUZZLE.Welcome to the medium to hard Sudoku book.Something for you to solve when you do want to think and engage your brain a little bit.The book is suitable for those who already have some experience playing the game of Sudoku. Although it is aimed toward an advanced sudoku player, intermediates are more than welcome to try!You certainly won't just fill in the numbers without any thought; you will have to pay attention to the rules of Sudoku and make sure no numbers are repeated in any row, column or square.YOU WON'T GET BORED WITH THESE PUZZLES!