In 1793, a canal digger named William Smith made a startling discovery. He found that by tracing the placement of fossils, which he uncovered in his excavations, one could follow layers of rocks as they dipped and rose and fell—clear across England and, indeed, clear across the world—making it possible, for the first time ever, to draw a chart of the hidden underside of the earth. Smith spent twenty-two years piecing together the fragments of this unseen universe to create an epochal and remarkably beautiful hand-painted map. But instead of receiving accolades and honors, he ended up in debtors' prison, the victim of plagiarism, and virtually homeless for ten years more. The Map That Changed the World is a very human tale of endurance and achievement, of one man's dedication in the face of ruin. With a keen eye and thoughtful detail, Simon Winchester unfolds the poignant sacrifice behind this world-changing discovery.