Build up your sudoku skills from easy to expert! In this three-book series, each book helps solvers build their skills to get from one level to the next. Medium to Hard will build on the skills learned in the first book, Easy to Medium, gradually introducing more advanced techniques (like jellyfish and finned X-wings) alongside puzzles designed to hone those skills, giving solvers plenty of opportunity to practice, and to build the confidence to continue on to the next volume.