A new documentary and biography claim late American author J.D Salinger left detailed instructions for at least five new books to be published.
The reclusive author of Catcher in the Rye last published in 1965, and lived in seclusion in New Hampshire in the north-eastern United States until his death in 2010 aged 91.
While those close to him said he continued to write, what he was working on has long been shrouded in mystery.
The New York Times on Sunday reported that a new documentary and book, both titled Salinger, include detailed assertions Salinger left orders for his estate to publish at least five additional books.
The release of the unpublished work - including new stories about the Glass family who have featured in a number of his stories such as Franny and Zooey - is set to take place between 2015 and 2020.
Another one of the books due for release is The Last and Best of the Peter Pans which was known to exist as an unpublished work.
The new works also include fresh stories about Holden Caulfield, who generations of readers know from the Catcher in the Rye, as well as a novel based on his relationship with his first wife, and a novella modelled on his own war experiences.
The book and film cite two "independent and separate" anonymous sources for the information on the planned posthumous works.
The documentary is a result of nine years of research by filmmaker Shane Salerno, and will be released on September 6.
The accompanying book is co-written by David Shields and will be published on September 3.