In the eighteenth century, the received wisdom, based on biblical calculations, was that the Earth was just six thousand years old. James Hutton, a gentleman with a passion for rocks, knew that could not be the case. Looking at the irregular strata of the Earth he deduced that a much longer span of time would be required for the landscape he saw to have evolved. In the turbulent world of Enlightenment Scotland, he set out to prove it. Hutton's entourage in Edinburgh comprised the leading thinkers of the age, including Erasmus Darwin, Adam Smith, James Watt, David Hume, and Joseph Black. But his geological theories would ignite decades of profound religious debate. Ultimately, Hutton's discovery of deep time changed our view of the universe forever.