Why do people measure time? How have clocks changed the way people live? How may high-tech clocks improve life in the future? This volume from the "Inventions That Shaped the World" series is full of fascinating facts about the ingenious ways in which humans have measured the passage of time. Series Information: Inventions That Shaped the World introduces young readers to revolutionary inventions, and emphasizes the impact the inventions had upon life at the time of their creation and beyond. Also explored is the featured invention’s cultural significance, as well as the patterns of change that resulted from its origination. Chapters cover topics such as life before the invention, the need for the invention, its development, its influence upon culture, its evolution, and a biography on the inventor.