128 very difficult Sudoku Puzzles with instructions on solving them in a totally new way. As the puzzles get more difficult, the process of penciling in partial solutions in each square, erasing and repeating a bit messy and prone to errors. In this book all the "number possibilities" are lightly penciled in each square. Simply cross out the "non-possibilities." Start the elimination process in each 3x3 square and then continue vertically and horizontally. Continue solving the puzzle as you have done in the past. You will find that you are able to solve the puzzles quicker and less likely to make a mistake.