To feed the nation's addiction further, here is the sixth installment of The Times Su Doku puzzles.

Beguiling and gratifying, Su Doku is the mind-flexing way to pass free time. This handy pocket-sized Su Doku book is perfect for people who enjoy Su Doku in any setting: in the park, on the train, or on the go.

Aims to help you find the perfect sudoku challenge and become a master. Just like karate, these puzzle collections are ranked by different-colored belts and they're organized by level. Beginners can move from book to book as their skills improve. By the time they reach Black (Level 9), they're ready to take on super-tough sudokos.

Features 201 fiendishly difficult puzzles in five excruciatingly advanced levels, for the really skilled and dedicated Sudoku fan.

The first Times Su Doku book sparked a worldwide publishing phenomenon -- sales have topped 4 million copies worldwide since March 2005.

Part of a series that is designed to help you make the most of your brain power by solving puzzles that increase slowly in level of difficulty, this title contains difficult puzzle-types like Detail Scenes, Match 1 and Mirror Image, as well as some tough logic problems.

This fully revised compilation of 'The Collins New Quiz Books' offers yet more fun multiple-choice remedies for the inquisitive; designed for all social gatherings, especially family get-togethers.

Beguiling and gratifying, Su Doku is the mind-flexing way to pass free time. However, these addictive puzzles often encroach upon more than a solver's spare moments. And now, Pocket Su Doku further enables obsession. This handy book makes it almost too easy to have the puzzles at arm's reach, ready to befuddle and stimulate anywhere, at any time.

Samurai is for those who wants to enjoy extra-challenging extended-length Su Dokus. Samurai Su Doku is a five grid interlinked Su Doku. This book features 100 puzzles, split between 4 levels of difficulty, with a few very easy puzzles at the start and a few super difficult puzzles at the end.

The ultimate Su Doku challenge from Wayne Gould, the man who started it all.

A brain training puzzle book that includes over 400 puzzles and solutions to help you reach your maximum mental potential. Organized by difficulty and type, it includes various things from language puzzles, letter equations and logic puzzles, to math and science teasers, probability puzzles, rebuses, riddles and trivia.

A collection of puzzles designed to test your brain-power and to improve your mental agility.

An IQ test book that features 12 tests and over 400 questions. It includes a wide range of simple, high-ceiling, and culture-fair tests, covering various things from verbal intelligence, to logic and reasoning.

The final title in a trio of books from the Su Doku master, Wayne Gould. Take your skills to a new level with these fiendish, challenging and addictive puzzles to keep your brain sharp all year round.

The ultimate Su Doku challenge from Wayne Gould, the man who started it all.

Codewords have been one of The Daily Telegraph's most successful puzzles since their introduction to the paper in summer 2003. This collection contains 150 puzzles.

Test your reasoning ability and your vocabulary with these teasing crosswords, where each letter of the alphabet is represented by a number. As you work your way through the grid, completing words using the letters you already have and perhaps a bit of forethought, you'll be able to assign numbers to letters until you complete the alphabet - and the puzzle! If you've always fancied yourself as a .

Su Doku 'the crossword without words' comes with a health warning : it is seriously addictive. Here is a third collection of 100 previously unpublished puzzles for those in need of a fix.