The fourth collection of the best-selling Times Su Doku puzzles,with exclusive `Alpha Doku' letter puzzles. The Times Su Doku Book 4 includes exclusive `Alpha Doku' LETTER PUZZLES 5 Easy Puzzles30 Mild Puzzles5 `Alpha Doku' Letter puzzles40 Difficult puzzles20 Fiendish puzzles For those still in the dark, Su Doku is a number grid consisting of 9 large squares each divided into 9 smaller squares. You must complete the grid so that every column, every row and every 3x3 box contains the digits 1 to 9. Wayne Gould, 59, is the brains behind this new craze. Now retired, he was a High Court judge in Hong Kong. People everywhere are crazy about Su Doku. Find out what all the fuss is about by having a crack at The Times Su Doku, the original, the best and the market-leader.