Taking the reader on a trip through time and around the globe, this guide charts the growth and development of the world's various timekeeping systems. It also describes the feasts and festivals connected with humanity's efforts to measure the passage of time. As well as describing our own Gregorian calendar, this book explains the cultural and religious influences behind the development of a wide range of calendar systems including systems as diverse as Aztec, Greek, Navaho and Zoroastrian.