What is the title of Copernicus's book outlining the heliocentric model?

Copernicus’s book outlining the heliocentric model is titled De revolutionibus orbium coelestium. The Latin title is commonly translated as On the Revolutions of the Heavenly Spheres. Its first edition was printed in Nuremberg in 1543 by Johannes Petreius, shortly before Copernicus died.

The book presented a mathematical alternative to the long-established Ptolemaic system. It argued that Earth rotates daily and travels around the Sun, while the other known planets also orbit the Sun. Copernicus still retained ancient assumptions such as perfectly circular planetary motion, so his system continued to use complex mathematical devices, including epicycles.

The title is often confused with later works associated with the Scientific Revolution. Galileo wrote Dialogue Concerning the Two Chief World Systems, and The Starry Messenger reported his telescopic observations. Principia is Isaac Newton’s landmark work on motion and gravity. De revolutionibus, however, was the foundational 1543 book that made Copernican heliocentrism a major subject of European astronomy.