What's Your Sudoku Strategy? Challenging Puzzle Books One-a-DayPaperback, 20 September 2017

Sudoku is all about getting the right strategy. You have to figure out how to fill the boxes and with what numbers. The only way to do that is to practice regularly. For that purpose, you have this big book for company. You can use the puzzles for trial and error until you can come up with a sound strategy that you can use. Good luck!