For puzzle solvers who want the ultimate sudoku challenge, The Independent Book of Super Sudoku takes these addictive brainteasers to a new level with an expanded 4-by-4 box. The idea remains the same as ordinary sudoku, but the larger grid adds a whole new dimension of complexity. Now puzzle users must fill in a 16-by-16 grid so that every row, column, and 4-by-4 box contains the digits 0 through 9 and the letters A through F. More challenging and more time-consuming, with three times as many squares per puzzle, this book is sure to please all sudoku fans.