WASHINGTON — Vanity Fair's big scoop almost didn't happen. It started with a cold call two years ago from John O'Connor, a prominent lawyer in the San Francisco Bay Area, to the magazine's editor, Graydon Carter. O'Connor, according to David Friend, an editor at the magazine, said he had a client "who is Deep Throat, and he wants to come out in the pages of Vanity Fair."

And so began the drama that led to Vanity Fair's revelation yesterday that former FBI official W. Mark Felt was journalist Bob Woodward's famed anonymous source on the Watergate scandal. Woodward's subsequent confirmation filled in what former Post executive editor Ben Bradlee yesterday called "the last act, the last unknown fact" about the events that led to the downfall of President Nixon.

Guessing at the identity of Deep Throat has been a Washington parlor game and journalistic sub-industry for almost 33 years.

They wanted money

The problem for Vanity Fair, Friend said, was that O'Connor wanted the magazine to pay Felt and Felt's family for the story — a condition the magazine would not agree to.

O'Connor — who had become acquainted with the Felt family through Felt's grandson, a Stanford classmate of O'Connor's daughter — decided instead to publish Felt's account as a book. But after a year of trying to find a publisher, Friend said, O'Connor was back at Vanity Fair's doorstep.

Therein began a long, secretive process to render Felt's story into print. Although O'Connor was the lead writer, the magazine supplemented his work with research and fact-checking. Felt's daughter, son, daughter-in-law and a former companion confirmed that Felt had previously revealed his identity as Deep Throat.

About 15 Vanity Fair editors and staff people eventually were assigned to the story, code-named WIG (a corruption of "Watergate"). All of those involved signed confidentiality agreements that bound them not to reveal Felt's identity if the piece didn't meet publication standards.

The concern about leaks was such that Joan Felt, Mark Felt's daughter and a key source on the story, began referring to her father as "Joe Camel" — a nickname for a man with one of the most famous nicknames of the past 30 years. As the magazine moved toward publication, editors used a dummy cover line to shield their story as it went to the printer: "The Car Door Slams."

Friend said neither Woodward nor his Watergate reporting partner, Carl Bernstein — a Vanity Fair contributing editor — knew about the story until Friend e-mailed them a copy of it yesterday morning. "We felt that if we let Bob or Carl know, The Washington Post would be out before us," said Friend, the lead editor.

The Post was scooped, after keeping Felt's secret for more than three decades.

Although Woodward had checked in with the Felt family periodically, and is writing a book about his relationship with Deep Throat, Post Executive Editor Leonard Downie Jr. said Woodward never was told by Felt or his family that he was going public. "Bob was really kind of helpless" because Felt never indicated that their agreement was over, Downie said.

Confirming the story

Woodward and The Post decided to confirm Vanity Fair's story yesterday because "Felt's family and lawyer made their decision for him, and we had no choice," Downie said.

The mystery and celebrity of Deep Throat grew for three reasons: His revelations were critical in keeping Woodward and Bernstein focused on the Watergate story; his shadowy portrayal by actor Hal Holbrook in the Oscar-winning "All the President's Men" in 1976; and the fact that his identity was held so closely for so many years. Bradlee said that until recently he, Bernstein, Woodward and Woodward's wife, Elsa, were the only people other than Felt who could confirm Felt's secret.

Bradlee said neither Katharine Graham, the late chairman and chief executive of The Washington Post Co., nor her son and successor, Donald Graham, asked for Deep Throat's identity. "I don't think I would have told them if they had," he said.

Vanity Fair's story hinted at but did not answer a key journalistic question: Was Felt, 91 and in ill health from a stroke, of sound enough mind to have confirmed his identity to O'Connor, or to have told Woodward that their agreement had ended?

The Vanity Fair story muddies the issue somewhat. O'Connor notes in the story that Felt told him, "I'm the guy they called Deep Throat," but the context is lacking. For one thing, O'Connor played a dual role: He was providing the Felt family with legal advice while also writing a magazine story, which meant that Felt's revelation may have been information provided under attorney-client privilege and therefore not subject to unilateral disclosure.

What's more, as O'Connor makes clear in his story, the Felt family was seeking to profit from Felt's secret identity and therefore had an incentive to pressure a clearly conflicted Felt into going public.

Despite personal and professional reasons to leak to Woodward, Felt long has denied that he was Deep Throat. He denied it when Slate's Tim Noah asked him directly in 1999, just as he denied it in his 1979 memoir, "The FBI Pyramid." Wrote Felt: "I never leaked information to Woodward and Bernstein or to anyone else!"