What better moment to ponder the concept of time than the dawning of a new millennium? This poetic and evocative work tells the story of how humankind has striven to capture time through the ages. From the earliest sundials to today's atomic clocks, we have slowly refined our ability to measure this powerful and elusive force, yet none of our clever instruments has ever been able to answer the age-old question -- What is time?

In this elegantly written new book, Barnett takes us a step further in our perpetual quest to comprehend time. She bridges the gap between the mechanical clocks which record the fleeting moment as it passes, and the powerful radioactive "clocks" which have opened up to us the eons of the earth's history. Beginning with a historical look at clocks to tell the time of day, she discusses the impact of such inventions and explains how they've gradually transformed our perception not only of the world, but of time itself. Each new advance -- from the early attempts to measure longitude, or endeavors to coordinate train schedules, to the centuries-long struggle to discover the age of the earth -- has opened the human mind to a deeper understanding of the concept of time, and has forced us to find new ways to think about this mysterious phenomenon that slips through our fingers, yet leaves its indelible mark upon our earth.