Test your powers of logic with these fun Su Doku puzzles.

Su Doku is the classic number puzzle.

The Times Su Doku Book 13 contains a mix of 150 mind-bending variations, ranging from mercifully Mild to the uber-challenging Super fiendish:

10 Mild puzzles 60 Difficult puzzles 50 Fiendish puzzles 30 Super fiendish

This latest edition offers completely new and unpublished puzzles, provided by the puzzle suppliers to The Times, and are of the highest quality.

So sharpen your wits and prepare to get solving - the only question is: can you make it to the end?