The Pros: The book is fairly small and easy to take with me when I know I'll have time to kill. There's just one puzzle per page, so there's enough room to pencil in up to four numbers per box. There's 319 puzzles in total, and solutions for all 319 in the back of the book. The Cons: I don't know that there's a uniform standard in the Sudoku world for what constitutes an expert puzzle vs. a difficult one. However, this book uses both terms to describe all of the puzzles ("expert" on the cover and "difficult" above each puzzle). To me, that's conflicting. What I do know is that I completed puzzles 1-12 first, then I skipped to the last four puzzles. The last four puzzles were a bit more difficult than the first twelve. Fourteen of the sixteen puzzles I've completed did not require any advanced strategy. Only two required the X-Wing strategy, which is not super advanced. So, I'll continuing my way through the book, but will now go backwards from last puzzle to first, for as long as I can stay engaged. I'll probably end up trying to find a TRUE expert book (if there is one) or at least something more advanced. The problem is, the marketers use terms like Extreme, Black Belt, World's Hardest, Nasty, and Genius Level to entice puzzlers to buy their books. Again, there's apparently no standard for difficulty in the Sudoku world, so you don't really know what you're getting until you buy it. Come to think of it, I believe that's the winning strategy! (for the sellers).
