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

Su Doku, the wordless crossword in The Times, has taken the puzzle world by storm.This is the first and only official book of the puzzle, certain to satisfy the many fans of this exciting new brainteaser.

Su Doku is the biggest craze to hit The Times since the first crossword was published in 1930. From obscure origins, the wordless puzzle is now the hottest challenge to readers of The Times and has generated a huge postbag at the newspaper's offices. Emails and letters have been arriving by the thousand each day.

Here, for the first time, is a collection of 100 never-before-published puzzles ranked in order of difficulty. They have been created by Wayne Gould who sets the puzzle for The Times.

Wayne Gould is the brains behind Su Doku. A former High Court judge in Hong Kong, he now spends his time developing the puzzle.