The Epitome Astronomiae Copernicanae was an influential astronomy book on the heliocentric system published by Johannes Kepler in the period 1617 to 1621. It contained in particular the first version in print of his third law of planetary motion. The work was intended as a textbook, and the first part was written by 1615. Divided into seven books, the Epitome covers much of Kepler's earlier thinking, as well as his later positions on physics, metaphysics and archetypes. In Book IV he supported the Copernican cosmology. Book V provided mathematics underpinning Kepler's views. Kepler wrote and published this work in parallel with his Harmonices Mundi (1619), the last Books V to VII appearing in 1621.