The best-selling book of 1981 was "The Simple Solution to Rubik's Cube" by James G. Nourse. The book explains how to solve the classic Rubik's Cube puzzle. It was extremely popular during the 1980s, as the Rubik's Cube craze swept the world.
The best-selling book of 1981 was "The Crossword Puzzle Dictionary" by Andrew Swanfeldt. The book was a comprehensive guide to solving crossword puzzles, and was the best-selling book of the year.