Absolutely Nasty Sudoku: Even Nastier – Level 4

Gluttons for punishment rejoice! The popular series of ultrahard sudoku is back. Just when it seemed safe to go back into the puzzle section of the bookstore … here comes another collection of the hardest sudoku known to humankind. The newest four volumes of this bestselling series range from Level 1 to Level 4, increasing in difficulty as they go. In Level 1, solvers will encounter 242 puzzles difficult enough to make them say, “Wait … this is the easiest level?” After the book is complete, three more levels await those who are daring enough to continue!