H. R. Haldeman, Frank Snepp, Elizabeth Ray and David Rovik have little in common except books, specifically books that became best sellers in the aftermath of front page newspaper publicity.

Haldeman's "Ends of Power" was rushed into shops ahead of its release date after The Washington Post obtained a copy and reported its content Rorvik's "In His Image: The Cloning of a Man" was also published two months early after newspapers and magazines related the author's fantastic story of a baby allegedly created in a laboratory. Snepp's "Decent Interval," an account of CIA ineptitude in Vietnam, was released only after copies of the book has been carefully leaked to selected journalists, and Ray's "Washington Fringe Benefit," was rushed out after The Washington Post revealed that the author had in effect been placed on the government payroll to be the mistress of former Rep. Wayne Hays.

The publication this week of the serial rights to richard Nixon's memoirs is part of a carefully orchestrated plan to maximize the profits of the book. On Monday selected reviewers will receive copies of the 1,200-page tome, and one week later the $20 book will appear in shops.

There's no way to tell how the Nixon book will sell, particularly in light of its hefty price tag. Haldeman's book has reached a print order of 400,000 Rorvik's 100,000, Snepp's 65,000 - all substantial figures for hardback books. Ray's - paperback original - has hit a whopping 1,725,000 copies in print.

"The whole point of this," says Irving Lazar, agent to Nixon and other six-digit advance authors, "is to what peoples' appetites. Getting books onto the front pages of newspapers has become an accepted world of its own now. Remember the Judith Exner book (by a witman who claimed to be a former mistress of John Kennedy)? The newspapers created that book!"

"It used to be," says Little Brown's William Guthrie, "that movie magazines were the dubious glamor children of culture. Now front pages are filled with tittle-tattle. I mean, none of the Watergate books seems to agree."

Except for Rorvik's clone book, most of the volumes winding up on page 1 have been politically oriented.

"That's what the news media is interested in," says Harriet Algrant of Random House," publishers of the Snepp book. "Since Watergate we've seen John Dean and then Haldeman and now Nixon as front page contenders. Obviously it makes people in the book business ask questions like: 'Is Bert Lance going to do a book? Will he be able to make some sort of newsworthy disclosure?'"

In the case of the Snepp book, Random House took enormous secrecy safeguards to keep the book from the CIA. The company had decided to leak a copy of the book exclusively to the New York Times, in hopes of generating front page publicity (which it did), and on the same day The Washington Post also obtained a copy of the book and ran its own front page story.

"There's no question that when a book is in the news, it keeps the book in the public eye," says Knopf's William Loverd.

"Books have become a new form of journalism," says Tom Lipscomb president of Times Books. "It was only five years ago that we found out - in a book - that the German intelligence was right in ascertaining that the Lusitania was in fact carrying arms.

"The simple fact is that more people read the front page than the book reviews. The publishing business realizes that.Books are getting more like long news stories. "It's like giving a reporter $20,000 and saying, "Track that story down and turn it in when you've got it nailed solid.'"

Part of this interest in newsy books is based on readers' preference for nonfiction over fiction - at least two to one for best sellers. And then there was Watergate, which seemed to spawn books the way the Yankees buy ball players.

"It's a far cry from Maxwell Perkins," says Guthrie, referring to the eminent Scribners' editor who single-handedly whipped the manuscripts of Thomas Wolfe into shape, "when men in tweeds discussed outlines in oak-lined rooms. Public figures who quietly used to assemble their memoirs in the twilight of their years are being recruited by Swifty Lazar into sideshow specters."

Lazar himself says "publishing today is show biz. You walk into Random House or Knopf or Simon & Shuster and they look like movie moguls; they don't look like publishers. I mean, they're doing million dollar deals."

Says Guthrie: "When you have New York Times Company (publishers of the Haldman book, as well as sellers of the Haldeman and Nixon serializations) swearing people to secrecy to protect product, that's big money. That's high stress. There's so much money tied up in these things that the publisher just has to do almost anything to make it profitable."

Times executive editor A.M. Rosenthal says, "I don't know wheter we sell any books with stories on the front page about them. Did we sell David Frost's book on Nixon because we ran a story about what he said? I can assure you that we didn't do it in order to sell any books.

Sometimes the line separating news and promotion can be thin. The Washington Post, for instance, knew that Elizabeth Ray was writing a book about her sexual dalliance with members of Congress before it ran its story on her.

"You run it for its news sake or you don't run it for its news sake," says Post executive editor Benjamin Bradlee. "You don't really have any control over what people you're writing about are doing on their own. I don't know if we helped the Ray book with our stories, just as I don't know if we helped sell the Haldeman book. Nixon's the more interesting case to me. What do you pay for these things?

Why should you pay at all? The prices are so out of line." (Up to $50,000 for newspaper serialization.)

"When you have so much invested in a book," says Harold Roth, president of Nixon book publishers Grossett & Dunlap, "anything that will get the book talked about beyond the book page is very important."

Sometimes this can work to a publisher's disadvantage. When word of Rorvik's clone book leaked out two months before the book was due, Lippincott had to rush the work into print.

"Front page publicity is great," says Ed Burlingame, senior vice president and editor-in-chief at the house, "but only if you have books to sell. We had to get 80,000 out in three weeks, and that's not easy."