Mensa's Most Difficult IQ Puzzles: Take on the ultimate challenge by solving these demanding conundrums

Mensa's Most Difficult Pattern Puzzles: Unleash your creative problem solving to crack...

Mensa Mental Challenge: Exercise your mind with these colourful puzzles

Mensa Killer Sudoku: More than 200 of the most difficult number puzzles

Mensa Riddles & Conundrums: Over 100 Fiendishly Challenging visual, logic and number...