23 books • 4 series
Book #1: Best Average Sudoku 1
Book #2: Best Average Sudoku 2
Book #3: Best Average Sudoku 3
Book #4: Best Average Sudoku 4
Book #5: Best Average Sudoku 5
Book #1: Best Hard Sudoku 1
Book #2: Best Hard Sudoku 2
Book #3: Best Hard Sudoku 3
Book #4: Best Hard Sudoku 4
Book #5: Best Hard Sudoku 5
Book #1: Best Simple Sudoku 1
Book #2: Best Simple Sudoku 2
Book #3: Best Simple Sudoku 3
Book #4: Best Simple Sudoku 4
Book #5: Best Simple Sudoku 5
Book #1: Big Best Sudoku 1
Book #2: Big Best Sudoku 2
Book #3: Big Best Sudoku 3