The book contains 800 sudoku puzzles from the simplest to the really complicated ones. In the introduction, you will find the best tricks and advice on what technique to choose when solving puzzles to reach the master level. Frank Longo is the author of more than ninety successful books that have sold more than four million copies. He is a champion of Sudoku and, in addition to the basic puzzles that you don't find in magazines and newspapers, he also creates fiendishly difficult Sudoku that requires advanced solving techniques and is intended for all those who really want to torture their gray brain cells.