Feature●Get ready to take on these toughies... challenging, yet fun!●As you work your way through each volume, the puzzles will increase in difficulty from hard to challenger.●Each measures 7 1/2 x 10 3/4". 64 pages with 159 puzzles in each.●Volumes 4, 5, and 6●Please see all pictures for samples of puzzles you will find inside.Description Place a number into each box so that each row across, each column down, and each small 9 box square within the larger diagram (there are 9 of these) will contain every number from 1 though 9.