Galileo's scientific and literary masterpiece, arranged as a four-day dialogue between three participants. Their exchanges suggest to the reader that the Copernican model is distinctly superior. By comparison, the traditional hypotheses—including the one put forward shortly earlier by Tycho Brahe—suffer from insuperable limitations. The frontispiece by Stefano Della Bella depicts the imaginary conversation between Aristotle, Ptolemy, and Copernicus.