Eudoxus of Cnidus (Greek Eυδοξοσ) (circa 408 BC - circa 347 BC) was a Greek astronomer, mathematician, physician, scholar and friend of Plato. Since all his own works are lost, our knowledge of him is obtained from secondary sources, such as Aratus's poem on astronomy.
He was a pupil in mathematics of Archytas in Athens. In mathematical astronomy his fame is due to the introduction of the astronomical globe, and his early contributions to understanding the movement of the planets.
His work on proportions shows tremendous insight into numbers. He invented the method of exhaustion, which was used in a masterly way by Archimedes. The work of Eudoxus and Archimedes as precursors of calculus was only exceeded in mathematical sophistication and rigour by Newton himself.
An algebraic curve (the Kampyle of Eudoxus) is named after him