More than half of the volumes are heavily annotated and offer a fascinating insight into the character and working methods of one of the greatest novelists of this century.
Although his handwriting is small and spidery, his seemingly random thoughts are expressed with fluency and confidence. Perhaps because they were never intended for publication, the writings are personal and free.
Before his death in 1991, Greene passed the library to Nicholas Dennys, a nephew, to whom he grew close after 1979, when Mr Dennys became a second-hand bookseller; Greene once said that if he had not become a writer, that would have been his chosen career. Mr Dennys, who has been cataloguing the collection for the past two years, said that he had been unable to find any other major 20th-century novelist who annotated so intensely.
Robert McCrum, editor-in-chief at Faber & Faber, writing in The New Yorker, said: 'Greene's annotated library . . . gives the literary detective vital clues to aspects of his life that have until now remained hidden. . . a window on the mind and fancy of a major 20th-century writer. . .'
Mr Dennys said three-quarters of the library was devoted to literature; the remainder was made up of books on religion, politics, history and travel.
He described it as 'a unique archive . . . of the relationship between a writer's source material and his creative work'.
For example, there are 16 books with notes for The Comedians: Mr Dennys said that while writing this he seems to have read at least nine volumes of Chekhov. The books bear 1,400 words of draft manuscript for The Comedians, as well as an annotation of Chekhov's text, ideas for eight short stories, and notes for another novel, The Human Factor.
Greene is believed to have wanted the library to be sold so that the money raised would be used to care for his much-loved sister, Elisabeth Dennys, who suffered a stroke in 1989. Mr Dennys would not comment on the family's reasons for selling.
The sale is being handled both by Mr Dennys, at the Gloucester Road Bookshop in London, and Bloomsbury Book Auctions.
The library also includes more than 150 letters from literary and political figures, including the poet W H Auden.