DEBORAH DAVIS made a critical error in the way she build this book.

For most of the first 100 pages or so she wrote a fairly routine account of Katharine Graham's forebears and upbringing. It is the standard fare of biographies and interesting to me because I knew nothing about Mrs. Graham's father, Eugene Meyer, one of the founders of Allied Chemical and Anaconda Copper and a sometime elite bureaucrat. I was equally ignorant of Mrs. Graham's mother, Agnes Ernst Meyer, a close friend of Stieglitz and Rodin. Mrs. Meyer, despite her aloofness and egotistical silliness, impresses me as one heck of a charming person (a judgment, I gather from what Davis says, that Mrs. Graham would not share). And I was passingly entertained, for nostalgic reasons, by the account of young Katharine's mingling with the radical rabble at the University of Chicago in the 1930s.

Generally speaking, that section has the tone one expects of a writer who desires to be accepted in genteel society. And the same tone prevails over the next 70 or so pages in which Davis traces the destruction of Mrs. Graham's husband, Philip. Suicides have an unfortunate way of casting a melodramatic light on everything that preceded them in the victims' lives. It's pretty hard to put together the stuff of Philip Graham's career -- Felix Frankfurter's blessings, JFK's friendship, violent escalations and plummetings of spirit, miserable end -- without sounding a bit excessive, and I think Davis did a creditable job of keeping herself and her material under control.

But then she made her big, big mistake. She tried to attach the orthodox opening to an unorthodox end. Biographer Jekyll became Hatchetwoman Hyde. She put aside her factual suit, donned a tight opinion skirt slit up the bias, and set out to have a swinging time. But the two halves just won't stick together. This book is schizo.

As a lifelong practioner of irresponsible journalism, I want to give Davis some advice. There's nothing wrong with using a hatchet or stiletto. You can get by with some wild and woolly theorizing, and many people will enjoy your work, and most will tolerate you so long as you come on honestly with your weapon in clear view from the first and don't pretend objectivity for one moment. But people will feel they have been tricked and will never forgive you if you approach in the guise of a legitimate biographer or historian and then switch.

In her new role, Davis portrays Mrs. Graham as a patsy for politicians, and she portrays the Post's top editors as tools of the intelligence community. The exposure of the Watergate scandals was, we are told, nothing but the manipulation of the Post by the CIA, which wanted to get rid of a president it looked upon as a threat to its bureaucratic existence.

Which is not to say Davis doesn't make some good points in the second half. She argues that the Post -- and particularly Mrs. Graham -- was suckered by Lyndon Johnson and Henry Kissinger on the Vietnam war, and that's easy enough to believe. Certainly the Post (and The New York times, as well as most of the press) was shameless, unconscionable, ruthless, and stupid -- a word I think the Post's management will itself someday admit the accuracy of -- in the way it went on and on and on editorially supporting that wretched war. But of course Davis is hardly the first, and she is certainly not the most eloquent, to make those accusations.

I am quite willing to believe the CIA would like to claim such powers, but Davis has, at best, fragmented evidence that the Post's support of the war was also heavily due to personal and professional alliances between certain editors and certain spooks. (Oddly enough, in putting together her "network" she neglects to mention that Philip Geyelin, the former editor of the Post's editorial page, had once been a CIA employe. Perhaps it's because Geyelin was more critical of the war and thus did not fit her thesis.)

Newspaper people with friends at the CIA are just as likely to exploit those friendships to undermine the CIA as to support it. Or, if not just as likely, at least quite capable of doing so, as some have shown.

A much more reasonable explanation for the Post's conduct during the Vietnam war is given by Davis on the very first page of the book, where she writes: "As in all cities, that dominance [of the Post in Washington] means that the publisher has close social relationships with the city's important politicians, and that they influence her newspaper, just as her newspaper influences them."

Of course this is exactly what happens, and these social ties are often harmful. But Davis fails to acknowledge the rest of the equation. First of all, a rich publisher who wants to be a mover and shaker will invariably hire a smart, tough, ambitious editor who in turn will hire some smart, tough, ambitious lesser editors who will hire some smart, tough, ambitious reporters -- and when that churning mass of egos is uncorked, there isn't a chance in the world of the publisher's maintaining steady "control" up and down the line. Though it does not always work, the resulting corporate anarchy is the public's salvation. Mrs. Graham's sympathies for and financial connections with Allied Chemical did not prevent Post reporters from writing such detailed stories about the pollution of the James River as to shred Allied's reputation. On the editorial page the Post is scandalously pro-oil, but its energy reporters regularly come up with plenty of stuff to embarrass the oil industry and keep it on the defensive.

Davis also fails to include in her equation the recognition that virtually all blockbuster news stories that emerge from Washington are the result of the press being "exploited" by people in government who usually have a very selfish reason for spilling the beans. Who cares how selfish or devious they are, so long as they keep spilling? Deep Throat's motives were probably not very lofty, but the nation need be no less grateful for the results.

Harcourt Brace Jovanovich should be ashamed for not giving Davis better guidance and better editing for her first book.