Galileo’s Dialogue Concerning the Two Chief World Systems compares the Copernican or Heliocentric system with the Ptolemaic or Peripatetic, system of the cosmos. Published in Florence in 1632, it resulted in him being tried before the Inquisition. Using the dialogue form, Galileo masterfully shows the truth of the Copernican system that the earth revolves around the sun. The Dialogue is one of the most important treatises ever written. A work of supreme clarity and accessi...