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

Mensa's Most Difficult Maths Tests: Prove your arithmetic prowess by solving the...

Extreme Word Search Book for Adults: The Most Difficult, Hard, Ultimate, and...