Published by the National Geographic Society, this book chronicles the extraordinary origins of common tools, customs, and symbols that are taken for granted but essential to everyday life. The book details how the drink toast originated in sixth century B.C. when a host would raise a glass and drink with a guest to prove the beverage was safe and not a sinister plot to poison. It also explains the origin of common superstitions like knocking on wood, a 4,000-year-old practice initiated by American Indians to appease the gods after making a boastful claim. Inventions like the toothbrush (originally made from Siberian hog hair and bone), the zipper, indoor plumbing--which dates back 2,700 years to western India--and other humble-yet-indispensable items are explored with engaging, short essays. Hardcover; 303 pages.