About Time : Calendars

About Time Calendars explore different concepts of time. The book looks at the history and development of the calendar as related to timekeeping in general. Well-organized, clearly written two-page sections discuss various needs through the ages for keeping time, how different cultures have approached measuring it, and the problems of accuracy. Each spread includes color reproductions and photographs of sites, ancient calendars, and other artifacts. Using the same format, Earth Time explores geologic and evolutionary time from theories about the creation of Earth to the development of organisms and more complex life-forms. The different evolutionary eras and the types of life appearing in each one are covered. "Key Dates" boxes provide further information about the appearance of various life-forms, geologic changes affecting evolution, and names and discoveries of specific scientists or explorers. Full-color photographs, drawings, and reproductions illustrate the texts.