Mensa Sudoku

The Sudoku puzzles in this volume have been specially selected by experts at Mensa, the internationally renowned high-IQ society. Your objective: fill in the 9x9 grid so that each column, each row and each of the nine 3x3 blocks contain the numbers 1 to 9. The principle is elegant in it simplicity but, as you will discover, fiendishly challenging to master. Now you can enjoy the world's most popular logical puzzle while pitting your brain cells against the world's smartest minds.