THE TITLE SAYS IT ALL:
200 “Devilishly Difficult Sudoku Puzzles” for people who want to tax their brains and get a great sense of achievement.
Take time out from your busy schedule and have a little quality time with these difficult but fun puzzles.
This book is a collection of 200 previously unpublished Devilishly Difficult Sudoku puzzles. Perfect for the expert solver in need of a constant supply of difficult puzzles or someone wanting to take a step up in their sudoku ‘career’. This book will provide hours of absorbing, brain teasing entertainment.
You can find out more information here – https://www.amazon.com/dp/1071049178
If you are not in the USA then follow the above link and then Amazon will give you a link to your country’s local site. Try it. It only takes a few seconds to find your local Amazon page.