Epitome Astronomiae Copernicanae
The Epitome Astronomiae Copernicanae was an astronomy book on the heliocentric system published by Johannes Kepler in the period 1618 to 1621. The first volume (books I–III) was printed in 1618, the second (book IV) in 1620, and the third (books V–VII) in 1621. Content. The book 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. The term "inertia" was first introduced in the "Epitome". The first volume was put on the Index of Prohibited Books on 28 February 1619.