The puzzles in this collection of treacherously difficult puzzles will stretch even the most advanced Su Doku enthusiast. You will need to use all of your best

200 New Puzzles -- From Fiendish to Super Fiendish Su Doku, "the crossword without words," comes with a warning: it is seriously addictive. You don't need to be

A new collection of previously unpublished Fiendish Su Doku puzzles with the added bonus of 30 Super Fiendish puzzles. Perfect for the advanced solver in need o

Forget your classroom nightmares and discover how numbers can enhance and illuminate your world! How can math help you bet on horses or win in Vegas? What’s t

The Times Killer Su Doku is dangerously addictive. Here is a collection of 200 of the best Times Killer Su Doku puzzles to wrangle with over the holiday season.