It has been, as people always insist upon saying, as fascinating as a good detective story. Ever since the West German magazine bought the 60 black notebooks - and sold the rights to the Sunday Times of London, and almost sold them (for a rumored $3 million) to Newsweek - the Hitler diaries have been on trial, as it were. The unraveling mystery has proceeded with a hysteria not inappropriate to anything connected with Der Fuhrer.
At first it seemed fitting that Hugh Trevor-Roper, the British historian who verified Hitler's death for Winston Churchill, should be the one to declare of the diaries, dating from June 22, 1932, to April 1945, the month of Hitler's suicide: ''I am now satisfied that the documents are authentic.'' But only a few days later he backed off, announcing: ''I am not saying they are not genuine. I am saying they cannot be pronounced genuine.''
A parade of expert witnesses followed Professor Trevor-Roper to the stand, most of them with the word ''alleged'' on the tip of the tongue.
A noted historian of World War II, David Irving, introduced what may be known as the Ink Clue. Hitler, Mr. Irving argued, had a nervous twitch that forced him to write with a pencil. But after a look at the manuscript, Mr. Irving moved toward credulity even as Trevor-Roper moved toward doubt.
Then came the Incapacitated Hand Theory. Had Hitler's writing hand not been injured in an assassination attempt during his last year? The script did not show it.
At this point, the handwriting analysts flocked forward to complain that the penmanship looked too studied, too letter-by-letter, without that fine careless eccentricity most scribblers fall into owing to variations in mood or haste or fatigue.
As the sleuthing went on, the skeptics became more ingenious. Some decided it was all a communist plot - the work of a ''counterfeiting workshop'' in Potsdam, intended to divide West Germany and its current allies by salting old wounds.
But after all the heavyweight evidence by the experts, the argument that appeared to seize the public fancy was this: Hitler just didn't seem the ''diary type,'' as one doubter put it. A diary was ''out of character'' for Hitler, in the words of William Shirer, the correspondent who kept a famous diary himself on Hitler way back when - the best-selling ''Berlin Diary.''
We show our respect for the form of the diary, as we would for the love sonnet, by saying so emphatically to one another: Hitler? Impossible!
There are, of course, diaries and diaries. Samuel Pepys, with his urbane chronicles of dining out and his cheerful sign-off (''And so to bed''), is miles from Franz Kafka.
The diary of an adolescent, stammering to express inchoate feelings, is a universe apart from the diary of a general, summarizing a day's battle.
But, in one way or another, a diarist plays spectator to his or her own life - turning each day into a kind of snapshot for which one serves as photographer as well as subject, trying to achieve some vision outside of pure ego.
A diary may be - and often is - self-serving, but it is also a record and, like any record, runs all the risks of inadvertently telling the truth.
Autobiographies can be smoothed over - given a public face. A diary that is more than a mere logbook sooner or later blurts out secrets in the night. It not only spills what the diarist knows - it tells a little more. For a diary that plays the game fair surprises even its keeper. Oscar Wilde was, as usual, only half-kidding when he wrote, ''I never travel without my diary. One should always have something sensational to read in the train.''
Hitler's mode was the stadium speech - shrill, mass-hysterical. The scream does not work in a diary. It would be far easier for a forger to imitate Hitler's handwriting than to invent a diarist's voice for this man.
The excerpts ring curiously false. Is this evidence? Hardly the stuff Sherlock Holmes deductions are made of. The case is far from closed. But some logic of the heart insists: If Anne Frank kept a diary, Hitler didn't.