In a work entitled “On the Universe,” Aristotle argued that a 5th element, called ether or the quintessence, composes the celestial spheres that naturally rotate in place above the region where the four lower elements mix together beneath the Moon. The large, transparent, rotating spheres of quintessence carry the Sun, Moon, planets and stars around the central, stationary Earth, turning according to specific numerical proportions. Aristotle, a student of Plato and a teacher of Alexander the Great, set an astonishing number of fields on a productive footing through his comprehensive works. This is the first Greek edition of his collected works, published by the renowned early printer Aldus Manutius.