49 books • 11 series
Book #1: Easy Sudoku Puzzles Volume 1
Book #2: Easy Sudoku Puzzles Volume 2
Book #3: Easy Sudoku Puzzles Volume 3
Book #1: Faith
Book #3: Hard Sudoku Puzzles Volume 3
Book #4: Hard Sudoku Puzzles Volume 4
Book #2: Medium Sudoku Puzzles Volume 2
Book #2: Medium Sudoku Puzzles Volume 1
Book #3: Medium Sudoku Puzzles Volume 3
Book #4: Medium Sudoku Puzzles Volume 4
Book #1: Sudoku Puzzles Very Hard Volume 1
Book #2: Sudoku Puzzles Very Hard Volume 2
Book #3: Sudoku Puzzles Very Hard Volume 3
Book #4: Sudoku Puzzles Very Hard Volume 4
Book #1: Very Hard Sudoku Puzzles Volume 1
Book #2: Very Hard Sudoku Puzzles Volume 2
Book #3: Very Hard Sudoku Puzzles Volume 3
Book #5: Very Hard Sudoku Puzzles Volume 5