"After Galileo's trial and conviction by the Holy Office in 1633, he was placed under house arrest, and the Congregation of the Index forbade the printing of any of his books. To add to his woes, he was rapidly losing his sight, and the death of his beloved elder daughter in 1634 left him seriously depressed. Nevertheless, Galileo persevered with the Discorsi, and by 1635 had virtually completed the work. A manuscript copy was smuggled into France and later taken to Holland, where the Elzeviers in Leiden undertook its publication" (Norman).

"Considered the first modern textbook in physics, in it Galileo pressed forward the experimental and mathematical methods in the analysis of problems in mechanics and dynamics. The Aristotelian conception of motion was replaced by a new one of inertia and general principles were sought and found in the motion of falling bodies, projectiles and in the pendulum" (Dibner).