Sidereus Nuncius, or The Sidereal Messenger

Translation of one of the most momentous books in the history of science. Galileo's lucid explanation of his first telescopic observations of the sky, including the Moon, the Milky Way, but most importantly, his discovery and early observation of the Galilean moons of Jupiter. The original publication widely introduced a major paradigm shift in astronomy to western Europe, introducing the evidence that would support the Copernican model of the solar system.