Sudoku Hard To Extreme: 400 Puzzles, Hard, Very Hard and Extremely Hard Sudoku to solve, Includes solutions.

This Sudoku book claims to contain Hard, Very Hard and Extremely Hard puzzles, which is why I purchased it. In my other Sudoku books, which contain Easy, Medium, Hard and Very Hard, I have to skip over the Easy and Medium puzzles to be challenged at all, which is a waste of money. My intent was to purchase a book that only included challenging puzzles. In this book, the Extremely Hard puzzles were not even that difficult. So, if you are experienced in Sudoku and are looking for a challenge, this is definitely not the book for you.