Sudoku addiction feeds the sales of this best-selling series. "Pocket Posh(R) Sudoku 21" presents a beautiful book of 100 Sudoku puzzles in 3 difficulty levels. Pocket Posh(R) Sudoku titles have combined sales of 1 million copies across the series. Hit the jackpot with "Pocket Posh Sudoku 21." Our 21st title in the series offers 100 fun and challenging Sudoku puzzles in three levels of difficulty. "Pocket Posh Sudoku 21" is perfect for puzzlers on the go. This portable package is part of a best-selling series featuring highly stylized, embellished covers and boasting 5 million copies in print. A free trial subscription to The Puzzle Society(TM) adds extra value.