About the Author
David Singmaster is a retired professor of mathematics at London South Bank University, England, who is most famous for his solution to the Rubik's cube.
Dieter Gebhardt has published over 70 articles on puzzles and is considered a leading expert in the field of rotational puzzles.
Jerry Slocum is a historian, collector, and author specializing in the field of mechanical puzzles. His personal puzzle collection, numbering over 40,000 mechanical puzzles and 4,500 books, is believed to be one of the world's largest.
Wei-Hwa Huang is a four-time World Puzzle Champion and one of the first few people in the world to have solved an actual 6x6x6 and 7x7x7 Cube.
Geert Hellings began collecting rotational puzzles in the early nineties and is currently the President of NKC, the Nederlandse Kubus Club (Dutch Cube Club), an association with 500 members from all over the world.