More than 200 never-before-seen Killer Sudoku of a progressive level of difficulty, complete with an introduction and full solutions.

Test your powers of deduction against more than 200 devilishly difficult Killer Sudoku puzzles.

The revered intelligence organisation, Mensa, have worked with Gareth Moore to put together a supreme test of logic. These brand-new puzzles will provide hours of entertainment for anyone who enjoys a difficult mental challenge.