Publishing a 5th volume of a book speaks of the quality of previous volumes more than words can tell. This is surely the most popular Killer Sudoku book series out there. All puzzles in this book are NEW. Difficulties are pretty much the same as before. Another sequel in the Killer Sudoku series of books from DJAPE. Brand new puzzles, with the same intensity and intricacy as the old ones. There are no trivial puzzles in this book - the accent is again on moderate and difficult puzzles. Contents: 100 Killer Sudoku 10 Killer Sudoku with diagonal cages 10 Diagonal Killer Sudoku X and 30 ZERO Killer Sudoku (blank cages) Difficulty levels are the usual EASY-COOL-THINKER-BRAIN-IQ. Most puzzles are of THINKER and BRAIN difficulties, with lots of IQs, too. Zero Killer Sudoku puzzles are mostly IQs, of course. This is certainly the darkest and the bloodiest Killer Sudoku book you'll find