Did You Know?

Illustrated with more than 500 photos and drawings, this is a compendium of facts that well-read individuals already know. A wide range of knowledge is covered (albeit sketchily and fragmentarily) in chapters on inventions, cosmology, geology, botany, biology, medicine, language, cities, the arts, etc. Empedocles's theory of the four elements is discussed without mention of the groundwork laid by the pre-Socratics, for example, and nothing is said about Edison's debt to Faraday, Maxwell and Herz. (May)