America's collective nostalgia for the Camelot era of John F. Kennedy is reflected in a flood of books scheduled for publication this fall, the 25th anniversary of Kennedy's assassination.

At least two dozen titles will join the more than 100 books about the Kennedy clan currently listed in Books in Print, the industry reference guide. Many are reissues of earlier books, with new introductions, forewords or afterword sections. Several are novels speculating on what might have happened had Kennedy lived, and one, Don DeLillo's "Libra" (Viking), is a novel whose protagonist is Lee Harvey Oswald.Others examine the Cuban missile crisis, the significance of the Kennedy image and the disaster-riddled Kennedy dynasty.

Because this year also marks the 20th anniversary of the assassination of Robert F. Kennedy, at least three books offer portraits of the former attoney general.

The plethora of Kennedy titles is "no coincidence at all in terms of the book-publishing trade," said Roger Donald, publisher of Little, Brown & Co., where four Kennedy-related books will be issued this fall. "The book publishers know there will be a tremendous focus of attention on the Kennedys, particularly John Kennedy.

"It's not that publishers are hyping it," Donald said. "I think it's responding to the very natural interest on the part of the public."

That interest is fueled, former JFK adviser Theodore C. Sorenson said, by the fact that "John Kennedy still has a very special hold on the mind and memory of the American people.

"He was the last president who left office, tragic as his departure was, with the American people feeling proud and confident about him," said Sorenson, whose 1965 biography "Kennedy" is being reissued by Harper & Row-Perennial, and who has written the introduction and commentary for " `Let the Word Go Forth': The Speeches, Statements and Writings of John F. Kennedy, 1947-1963," due out in November from Delacorte.

"There is a sense of loss, a sense of curiosity, a sense of what might have been - and all that went down the tubes," said Edwin O. Guthman, co-editor of "Robert Kennedy: In His Own Words," a joint publication of Bantam and 21st Century Books that has already appeared on several best-seller lists.

"Part of what we are seeing is indeed an evocation of a man and a period that held out a lot more hope and promise," Donald said. "There is a feeling now that we are in a lull. If life was very exciting intellectually in the country today, one wouldn't be turning back and looking at those days with so much interest."

In Concord, Mass., former Kennedy-Johnson administration adviser and speech writer Richard N. Goodwin insisted it was purely coincidental that his book, "Remembering America: A Voice From the Sixties" (Little, Brown), will be published this fall.

Still, Goodwin agreed, "There is an enormous interest in the '60s. The problems are not the same today as they were in the '60s, but at least then the country was attacking things and trying to resolve problems and facing up to things."