When Halley found out all that Newton had discovered (but not published) about Celestial Mechanics, he prodded the frequently lazy Newton to put his discoveries into book form, edited the book, and published it at his (Sir Edmund Halley's) own expense. He practically WROTE the book from Newton's cryptic notes. And he declined to have his name appear.

http://members.tripod.com/~gravitee/history.htm

The birth of the Principia may be traced back to a discussion in 1684 at the Royal Society. Astronomer Edmund Halley and architect Sir Christopher Wren suspected that there was an inverse square relation governing celestial motions based on Kepler's Third Law of elliptical orbits, but no one could prove it. They brought the question before Newton's arch rival Robert Hooke, who claimed that he could prove the inverse square law and all three of Kepler's laws. His claim was met with scepticism, and Wren offered a forty-shilling book as a prize for the correct proof within a two-month limit. Hooke failed to produce the calculation, and Halley travelled to Cambridge to ask for Newton's opinion. Newton responded with a typical lack of interest in work that he had already completed, that he had already solved the problem years before. He could not find the calculation among his papers and promised to send Halley a proof. Halley, suspecting the same bogus claim he had received from Hooke, left frustrated and returned to London. Three months later he received a nine page treatise from Newton, written in Latin, De Motu Corporum, or On the Motions of Bodies in Orbit. In it, Newton offers the correct proof of Kepler's laws in terms of an inverse square law of gravitation and his three laws of motion. Halley suggested publication, but Newton, reluctant to appear in print, refused. At Halley's insistence, Newton finally began writing and, with typical thoroughness, worked for 18 months revising and rewriting the short paper until it grew into three volumes. The Royal Society, having exhausted available funds on an extravagant edition of De Historia Piscium, or The History of Fishes, could not pay for the publication and so it was at Edmund Halley's expense that Philosophiæ Naturalis Principia Mathematica was finally published.