Dan Croker has two obsessions - Sudoku and frogs. So he just had to combine his loves and make the Famous Frog Sudoku books. This Brain Yoga Series Book contains 600 puzzles, 300 hard and 300 very hard, with 4 puzzles per page. Featuring a fun and colorful cover that is sure to brighten your day. Of course, you don't have to do yoga while you do these puzzles! Solutions are given at the end of the book. More Famous Frog Sudoku series - Sharper Pencil Series, Bathroom Sudoku Series, Beach Bum Series and Travel Series.