Each edition of the series contains Sudoku puzzles. The Sudoku puzzles are with 32 predefined numbers from 1 to 9. This gives the level of difficulty as . There are four puzzles per page whereby each number square in a Sudoku provides as you work through the puzzle. All puzzles can be easily solved by excluding numbers by process of elimination from other columns, rows, or boxes, leaving . This book contains as well as for each of the 1000 puzzles.