This fun puzzle book for adults has 100 puzzles. All puzzles are Classic Sudoku or variants of Sudoku and will challenge your math and logic skills. Printed two puzzles per page on 8.5 x 11 inch pages. Solutions provided at the end of the book. Types of puzzles included are: Classic Sudoku, Killer Sudoku, Jigsaw Sudoku, Sudoku X, Windoku, and Even-Odd Sudoku.