This is excellent fitness for the brain. Holmes is a collection of serious, classic Sudoku puzzles. Features: These puzzles are for adults and for adult children. 200 strong kakuro puzzles. 100 even odd diagonal sudoku hard - very hard levels. 100 even odd anti-diagonal Sudoku puzzles hard - very hard version. The book has download links for 500 puzzles. I hope you enjoy this book. Best regards, Basford Holmes