"In Nature's Clocks, Doug Macdougall tells the story of scientists seeking to understand the past and shows how they arrived at the ingenious techniques they use to determine the age of objects and organisms. Focusing on radiocarbon (C-14) dating - the best-known of these methods and the only one that can directly date once-living material - and several other techniques that geologists use to decode the distant past, Macdougall unwraps the past century's advances, explaining how scientists use radioactivity to determine the ages of our fossil ancestors such as "Lucy," the timing of the dinosaurs' extinction, and the precise ages of tiny mineral grains that date from the beginning of the Earth's history."--Jacket.