During the 1530s, rumors began to spread throughout Europe of a potentially revolutionary theory of how the heavens worked emanating from a small city in Poland. Its architect was a Polish cleric named Nicolaus Copernicus. Around 1514, Copernicus had written and hand-copied an initial outline of his heliocentric theory-in which he placed the Sun, not the Earth, at the center of our universe, with the planets, including the Earth, revolving about it. Titled his Commentariolus, it circulated among a very few astronomers. Over the next two decades Copernicus expanded his theory through hundreds of sightings, leading to a secretive manuscript whose existence tantalized mathematicians and scientists throughout Europe. In 1539 a young German mathematician, Georg Joachim Rheticus, traveled to Frombork to meet Copernicus; months later he departed with the manuscript for the book that would change the way we understand our place in the universe. Rheticus arranged for the publication of De Revolutionibus Orbium Coelestium (On the Revolutions of the Celestial Spheres)-legend has it Copernicus received a copy on his deathbed-and the book became one of the greatest change agents in history.In her graceful, compelling style, Dava Sobel chronicles the history of the Copernican Revolution, relating the story of astronomy from Aristotle to the Middle Ages. In its midst will be her play, And the Sun Stood Still, imagining the dialogue that would have transpired between Rheticus and Copernicus in their months together. As she achieved with her bestsellers Longitude and Galileo's Daughter, Sobel expands the bounds of science writing, giving us an unforgettable portrait of scientific achievement.