Over 200 large, full page sudoku puzzles. I call these "challenging" in that they are difficult enough to test your sudoku solving skills but they do not require the "advanced" solving strategies such as X Wings, Swordfish, XY Wings, etc. (I do have books of EXPERT puzzles that do require advanced techniques if this is your cup of tea).
This book is for experienced sudoku solvers. This is not a beginner's book so there are no EASY or MEDIUM puzzles. All 200+ puzzles have similar difficulty levels. Puzzle solutions are included in the back of this book.