The Hard Book Of Sudoku, Very Challenging sudoku books for adults, Expert level Sudoku, 50 challenges with solutions.: Test yourself on these hard ... 50 very difficult puzzles, Sudoku Puzzles
This is a very challenging book of 50 Sudoku puzzles, this has been created to really test your mind. The solutions are also provided incase you really do get stuck. One puzzle page allows for errors and testing out positions of numbers.