Brain Games Unusual Knowledge Word Search contains 70 word search puzzles and facts to keep your brain humming. Every puzzle is themed, and includes interesting bits of knowledge about science, history, inventions, and pop culture. Find hundreds of words related to the puzzle themes. Word lists and information are drawn from the The Book of Unusual Knowledge, ISBN-13: 9781450845809. Answer key found at the back of the book. Spiral bound, 160 pages.