Go!games Absolutely Addictive SudokuPaperback, 1 February 2013

240 puzzles to entertain your brain.

Sudoku at its finest, give your brain a workout with 240 new and innovative puzzles in a variety levels so everyone can play. Solvers will find this book irresistible, with puzzles appropriate for all levels that build in difficulty. Test your skills as you work your way up to the hardest "Big Mind Challenge" selection. To help you, there's an excellent introductory section with tips and techniques.
They're fun; they're entertaining; they're ABSOLUTELY ADDICTIVE!