When you buy this book you get an electronic version (PDF file) of the interior of this book. You can play the puzzles in this book on your mobile phone! Become a master in solving Sudoku. After solving all the puzzle in this book, you will be a Sudoku Pro. You start with easy Sudoku puzzle and you gradually build your way up to extremely difficult Sudoku puzzle. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 large print puzzle per page, with lots of white space for scribbling. Sudoku Travel Pocket Size Book 1 - 120 Easy to Extreme Logic Puzzles For On-The-Go Holiday Fun is a collection of 120 puzzle: 30 easy Sudoku 9x9 puzzle 30 medium Sudoku 9x9 puzzle 30 hard Sudoku 9x9 puzzle 30 extreme Sudoku 9x9 puzzle The goal of Sudoku is to fill in the empty cells, one number in each, so that each column, row, and region contains each number exactly once. I guarantee that every logic puzzle in this Sudoku puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzle in this book will appear in any of the other English PuzzleBooks.net books. Sudoku is also known as Number Place, Nanpure, Su Doku. Quite often Sudoku is misspelled as Suduko, Soduko, Sodoku, Sudoko, Suduku or Soduku.