A 1951 file photo shows J.D. Salinger, author of "The Catcher in the Rye," "Nine Stories," and "Franny and Zooey." The authors of a new J.D. Salinger biography are claiming they have cracked one of publishing's greatest mysteries: What "The Catcher in the Rye" novelist was working on during the last half century of his life. 

Photo Credit: The Associated Press