Some 3,000 books and more than 60,000 papers belonging to Greene, who died in Switzerland in 1991, were bought by the John J Burns Library of Boston College, Massachusetts, for about £1m after a fierce bidding war with several American institutions.
The Gothic library on the Boston College campus has gained a reputation for its holding of British Catholic authors, such as Greene. His collection will be kept together on display there, allowing scholars open access for the first time.
The sale is a great loss to Britain. The archive is unique in revealing both sides of the author's correspondence. Carpal tunnel syndrome, a painful disorder of the hand, prevented him writing his own letters. He dictated them at his French home and sentthe tapes to his sister, Elizabeth Dennys, in England. His secretary for 25 years, she typed the personal and business correspondence on to pre-signed notepaper and meticulously filed both letters to him and carbons of his replies at her Sussex home.
The purchase of Greene's library also represents a coup for Boston College because many of the 3,000 volumes were heavily annotated by the author, who often used the flyleaves to write diary entries and observations he later used in work. One set of Chekhov's works contains source material for several of Greene's short stories and three of his novels.
Sometimes the comments scratched in a tiny hand on the flyleaves reveal the relationship between the source and Greene's writing; sometimes they are sharply critical of the text or the author.
The library also contains numerous first drafts for Greene's novels, stories, plays and poems. The writer also used his books, many given by literary contemporaries such as Evelyn Waugh, Ford Madox Ford and Vladimir Nabokov, as makeshift files: they are stuffed with letters and photographs. Both the library and archive will shed light on a man who jealously guarded his privacy. They are said to demonstrate his sense of humour, loyalty, remarkable courtesy and the depth of his friendships.
The proceeds of the sale will pay for nursing for Mrs Dennys, Greene's former amenuensis. Now 80, she was disabled by a stroke two years before her brother's death.
Her son, Nick Dennys, a second-hand bookseller, was given the library by Greene in 1990 and it has been in store since then. He said yesterday that his uncle would have wanted the proceeds to pay for his mother's care: "I think he just wanted to make sure we could look after her."
Rupert Powell, a director of Bloomsbury Book Auctions, which conducted the six-month negotiations over the sale, admitted he was disappointed that a British university had not come forward.
"British institutions knew about the sale; we tried to get them interested, but in the end they couldn't compete with American universities," he said. "It was a shame but at least the papers and books have remained together and have gone to a good home."