The West German magazine Stern announced today that it had discovered and authenticated 60 handwritten volumes believed to be the secret diaries of Adolf Hitler.

The Hamburg-based weekly said that eminent handwriting experts and historians, including Britain's Hugh Trevor-Roper, had examined the diaries and proved to their satisfaction that the volumes were not forgeries.

Stern claimed that the diaries had been transported by a Luftwaffe plane as Hitler sought to transfer his headquarters in the last days of the war from Berlin to his residence near the Bavarian Alpine resort of Berchtesgaden. The plane crashed in what is now East German territory on April 21, 1945.

Although it would not declare when and where the diaries had been uncovered, Stern said it had located the grave of the doomed plane's pilot and tracked down eyewitnesses of the crash "who gave first clues to the contents and whereabouts of the plane's cargo."

First extracts from the diaries, which Stern says were written in black ink in 100-page volumes and embossed with the Nazi eagle and swastika, are scheduled to appear this Sunday in the London Sunday Times and in Stern early next week.

Trevor-Roper, author of "The Last Days of Hitler," has said he is convinced that the papers constitute Hitler's diaries. He intends to publish his reasoning and conclusions in the London Times on Saturday and to elaborate further on the discovery at a press conference in Hamburg on Monday.

Some West German experts, however, voiced skepticism about the diaries. Werner Maser, an author and expert on Hitler, said that while he had not seen the evidence he was inclined to believe the documents amounted to "pure sensationalism."

Maser said that Hitler suffered from palsy and his nervous, shaking hands compelled him to write in pencil rather than ink.

He also said that forgeries of Hitler memorabilia had become something of a minor industry in East Germany, where false documents are peddled to tourists to gain much-needed hard currency.

A spokesman for West Germany's federal archives, which are expected to acquire the papers after publication, could not be reached for comment. Stern's editor, Gunther Schoenfeld, refused to divulge further details other than the information in the weekly's prepared announcement.

"When you have kept a thing secret for three whole years, even from your own colleagues on the magazine, then you will understand that it can wait another three days," he said.

If the Stern discoveries prove to be true, the diaries could offer a treasure trove of insights into Hitler's demented psyche and the inner court of the Nazi leadership.

"After assessment of the diaries, the biography of the dictator and the history of the National Socialist Nazi state will have to be rewritten in many areas," the magazine said.

Stern said that besides the alleged diaries, it had also discovered other papers written by Hitler on his narrow escape from a bombing on July 20, 1944.

Historians agree that the plane which Stern says was carrying Hitler's personal papers and diaries from Berlin did crash. Hitler's personal pilot, Hans Bauer, cited the incident in his memoirs and said the dictator was dejected by the news shortly before his death.

But West German historians noted that while the plane was believed to be transporting documents of the regime, there was no evidence that the papers were Hitler's diaries. In his book, Bauer does not speculate on what the documents were.

Ever since Hitler committed suicide in a Berlin bunker as Soviet troops closed in, rumors have circulated sporadically that the dictator had maintained an extensive set of diaries like several of his Nazi colleagues.

Propaganda chief Joseph Goebbels, who also committed suicide with Hitler in the bunker, and the dictator's architect, Albert Speer, wrote voluminous diaries or memoirs about their experiences during the rise and fall of the Third Reich.

But the search for Hitler's lost papers has often been disdained by historians and students of Hitler's life who contend that he evinced no signs of a man who systematically wrote down his private reflections and experiences.

"It just was not in his character," explained Professor Eberhart Jaeckel of Stuttgart University, who recently edited a book titled "Adolf Hitler's Entire Writings 1905-1924."

"Hitler often said that people should not write and keep useless scraps of paper," Jaeckel added.

Washington Post staff writer Patrick Tyler contributed the following:

John W. Toland, Pulitzer Prize- winning author of several books on World War II, including two books on Hitler, said yesterday from his home in Danbury, Conn., that "it seems unbelievable, but there is a chance" that the Stern diaries are authentic.

"Hitler was a secretive man, a quixotic man," Toland said. "He was a workaholic who stood hours at his work. To write a daily diary of any length would take a regimen that he didn't seem to have. But just when you think you have people pegged, they do something unusual."

Toland said he was impressed that the diaries had been presented to handwriting experts who authenticated samples from the volumes. "Stern is a reliable outfit," said Toland. "It would be the ruination of that publication if this is faked--or, if they were taken in, it would be just as bad."

The 70-year-old author pointed out that because of the voluminous handwritten material, it would take a very sophisticated effort to fabricate a diary covering a lengthy period of time.

"It it were faked, you would need expert historians and, no matter how good you are, in a long thing like that you are going to foul up," Toland said.

"I think it is an important historical find," Toland said. "Of course, all diaries are self-serving no matter who writes them."

But, he added, "I hope it's true because it's going to help us understand Hitler better, and we need all the understanding we can get about him in the 20th century to better prepare us to live in the 21st century."