Newton published the Principia mathematica in 1687
The documents detail Newton's feuds with other scientists and his early years as a scientist. His death mask from King's College library is also on display.
Footprints of the Lion: Isaac Newton at Work will be displayed from Tuesday, after the library raised £6.37m to buy the Macclesfield collection of the scientist's papers.
Papers kept together
The library has been in possession of the Portsmouth collection - the principal archive of Newton's scientific work - since 1872, when it was presented to the university by the fifth Earl of Portsmouth.
But a £4.79m grant from the Heritage Lottery Fund and a comprehensive fundraising campaign last year enabled the library to purchase the second most important scientific collection.
"The collection was offered by the Earl of Macclesfield through Sotheby's, but we were given first refusal if we could raise the cash," said Cambridge University librarian, Peter Fox.
"We were afraid that if it had gone on the market, it would have been split up and sold to individual collectors around the world, because Newton is very collectable," Mr Fox explained.
"And that would be the end of it as far as scholars are concerned." The library was delighted to reunite the papers and keep them in this country, Mr Fox said.
"For the first time for several hundreds of years we are able to put together a more comprehensive picture of this man who shaped the world we live in today," he said.
"The collection shows Isaac Newton's creativity in letters and manuscripts on celestial mechanics and gravitation, his method of fluxions (the calculus), optics and chemistry.
'Complex story'
"Newton's manuscripts and books, some of which are from his own library, tell an even more complex story of this genius that is quite different from that of the alchemist and heretic, who had, for much of his life, lived a private life and deliberately avoided publicity of any kind," he said.
Born in Woolsthorpe, Lincolnshire, in 1642, Newton first arrived in Cambridge as an undergraduate at Trinity at the age of 19.
He was appointed a fellow of the college in 1667, and in 1669 was elected Lucasian Professor - the chair now occupied by Professor Stephen Hawking.
He died in 1727 and was buried in Westminster Abbey.
The Newton archives are on show to the public free of charge from 9 October to 23 March (closed over the Christmas week) at Cambridge University Library's Exhibition Centre.