Legendary author J.D. Salinger has passed away at the age of 91.

His most famous work, "Catcher In The Rye," written over sixty years ago, is still a best seller, and continues to remain popular with each new generation.

The Associated Press reports, "Salinger died of natural causes at his home on Wednesday, the author's son said in a statement from Salinger's literary representative. He had lived for decades in self-imposed isolation in the small, remote house in Cornish, N.H."

"Despite having broken his hip in May,” Salinger’s literary representative at Harold Ober Associates said in a statement, "his health had been excellent until a rather sudden decline after the new year. He was not in any pain before or at the time of his death.”

Although he only had a handful of books published in his lifetime, his decision to keep out of public and to keep his writing private has kept him in the limelight for decades. Numerous journalists have written stories about camping out at Salinger's in hopes of getting an exclusive. Reports through the years indicate that Salinger might have a backlog of yet-to-be-published work which may now possibly soon see the light.

In 2004, The Washington Post reported the 1951 "Catcher in the Rye" still sold "about 250,000 copies a year."

Last July, Judge Deborah Batts ruled in New York that Swedish author Fredrik Colting's book "60 Years Later: Coming Through the Rye" borrowed too heavily from the earlier work by Salinger.

The New York Times Company, the Associated Press, the Gannett Company and the Tribune Company, filed an amicus brief challenging the decision by a federal judge to prevent publication in the United States of the book.

The companies cited protection of free speech in the US constitution and common sense in urging the appeals court for the Second Circuit to overturn the order.

The media companies argued in their brief that "the only harm appears to be to the pride of a reclusive author in not having his desires fulfilled barring commentary about his iconic book and character, without any actual financial harm."

"Such a result defies common sense, and is not -- and cannot be -- the law."

Salinger's lawsuit argued, "Catcher is one of the all-time classic novels, achieving phenomenal and critical success. It has been named one of the 100 best novels by both Time magazine and The Modern Library, and is taught at schools around the country. It has been described in reviews as "a crucial American novel...," an "unusually brilliant novel" and "a cult book, a rite of passage for the brainy and disaffected." (The New York Times.)

"The Sequel is not a parody and it does not comment upon or criticize the original," Salinger's suit continued. "It is a rip-off pure and simple."

Mr. Salinger, who is fiercely protective of his intellectual property, and has never allowed any derivative works to be made using either The Catcher in the Rye or his Holden Caulfield character, did not and would not approve of defendants' use of his intellectual property. The right to create a sequel to The Catcher in the Rye or to use the character of Holden Caulfield in any other work belongs to Salinger and Salinger alone, and he has decidely chosen not to exercise that right. Indeed, in 1980, Salinger stated to the press, "There's no more to Holden Caulfield. Read the book again. It's all here. Holden Caulfield is only a frozen moment in time."

In December of 1980, Catcher received unwanted attention after John Lennon's assassin, Mark David Chapman, was arrested toting a beaten-up paperback copy with notes written in the margins.

Along with Catcher, Salinger's other published works include the also-highly-regarded 1953 short story collection Nine Stories, 1961's Franny and Zooey, and Raise High the Roof Beam, Carpenters and Seymour: An Introduction published in 1963.

In Salinger's New York Times obituary, Charles McGrath notes that "Joyce Maynard, with whom he had a 10-month affair in 1973," has "said she believed there were at least two novels locked away in a safe, although she had never seen them."

As for the fictional family the Glasses, Mr. Salinger had apparently been writing about them nonstop. Ms. Maynard said she saw shelves of notebooks devoted to the family. In Mr. Salinger’s fiction the Glasses first turn up in “A Perfect Day for Bananafish,” in which Seymour, the oldest son and family favorite, kills himself during his honeymoon. Characters who turn out in retrospect to have been Glasses appear glancingly in “Nine Stories,” but the family saga really begins to be elaborated upon in “Franny and Zooey,” “Raise High the Roof Beam” and “Hapworth,” the long short story, which is ostensibly a letter written by Seymour from camp when he is just 7 years old but already reading several languages and lusting after Mrs. Happy, wife of the camp owner. Readers also began to learn about the parents, Les and Bessie, long-suffering ex-vaudevillians, and Seymour’s siblings Franny, Zooey, Buddy, Walt, Waker and Boo Boo; about the Glasses’ Upper West Side apartment; about the radio quiz show on which all the children appeared. Seldom, in fact, has a fictional family been so lovingly or richly imagined.

Too lovingly, some critics complained. With the publication of “Franny and Zooey,” even staunch Salinger admirers began to break ranks. John Updike wrote in The Times Book Review: “Salinger loves the Glasses more than God loves them. He loves them too exclusively. Their invention has become a hermitage for him. He loves them to the detriment of artistic moderation.” Other readers hated the growing streak of Eastern mysticism in the saga, as Seymour evolved, in successive retellings, from a troubled, suicidal young man into a genius, a sage, even a saint of sorts.

But writing in The New York Review of Books in 2001, Janet Malcolm argued that the critics had all along been wrong about Mr. Salinger, just as short-sighted contemporaries were wrong about Manet and about Tolstoy. The very things people complain about, Ms. Malcolm wrote, were the qualities that made Mr. Salinger great. That the Glasses (and, by implication, their creator) were not at home in the world was the whole point, she said, which said as much about the world as about the kind of people who failed to get along there.

Salinger's death is likely to reignite speculation over whether he may have produced valuable works.

He hinted at this in a tantalising interview with the Boston Sunday Globe in 1980, where he said: "I love to write, and I assure you I write regularly. But I write for myself and I want to be left absolutely alone to do it."

The market for any posthumous Salinger writings would likely be highly lucrative.

Letters he wrote to his young lover Joyce Maynard, with whom he started a year-long relationship in 1972, sold for more than 150,000 dollars at auction in 1999.

(with AFP reports)