Sudoku: 96 hard puzzles: 4

A Sudoku puzzle book containing 96 diabolically difficult puzzles. The introduction includes brief instructions on how to play and solutions to all puzzles are included at the end of the book. This is the final book (ISBN: 978-0-6480782-7-2) in a series of four. The other three books are Sudoku skill builder which contains 96 puzzles at three levels of difficulty (book 1 ISBN: 978-0-6480782-4-1) Sudoku: 96 easy puzzles containing 96 easy puzzles for busy people (book 2 ISBN: 978-0-6480782-5-8) and Sudoku: 96 medium puzzles containing puzzles at a moderate level of difficulty (book 3 ISBN: 978-0-6480782-6-5).