No part of existence is more intimately familiar, yet more elusive and mysterious, than time. This wide-ranging, learned, and accessible book surveys the enormous variety of our understandings of time, both in the everyday world and in the specialized realms of the sciences and humanities. From the majestic visions of time and the timeless in major religions, derived from ordinary activity, J.T.Fraser offers the general reader a history of the idea and experience of time. The distillation of three decades of research, this volume considers such issues as the origins of the universe, relativity theory, the relation of inanimate to living matter, the biology of aging and death, the brain's perception of time, dreaming vs. waking reality, expectation and memory, the development of calendars and chronologies, the history of time-keep devices, the quantification of knowledge in Western society, and the relation of technology to the rhythms of collective life. Fraser discusses conceptions of time throughout history and explains his own original theory, which posits the existence of a hierarchy of temporalities - qualitatively different forms of time that operate at the levels of light, atomic particles, massive matter (stars and galaxies), living organisms, the human mind, and cultural systems. Throughout, Fraser writes not simply as a theorist of scientific knowledge, but also as a man of compassion and social responsibility. His vision of the human predicament is dark, but not without humour, and he offers a rebuttal to those who would espouse a simplistic, reductionist view of time.