The story of enigmatic scientist-turned-priest, Nicholas Steno, who first proposed that the shell-shaped rocks commonly found on Italian mountaintops actually were fossils—a notion completely antithetical to the 17th century theological and scientific world view, which maintained that the earth was only 6000 years old. Placing Steno's story in the context of such characters as Darwin, Newton, Thomas Jefferson and Saint Augustine, Alan Cutler illuminates the subject of "deep time" by combining authoritative science with stories of extraordinary people to bring home the philosophical and personal significance of Steno's ideas, offering a fresh, new perspective on the very old planet on which we live.