The key discoveries & theories that preceded Newton's work on gravitation are described: including those of Copernicus, Kepler, Descartes, Cassini, Huygens, Hooke & Roemer. Surprisingly there is no description of a major contribution from Galileo
- beyond his assertion that heavenly bodies are not perfect & cannot be placed above scientific reasoning. Three demonstrations of Newton's theories are also presented. That is proof of the flattening of the earth at the poles, by the French in 1735, predicting the re-appearance of Halley's Comet in 1759 & the existence of Neptune & the description of its orbit in 1846. Alexander Pope did not exaggerate, Newton's extraordinary mind drew together all the scientific knowledge of his day & moulded it into a theory that accounted for almost every observable fact.