In Washington's classic whodunit, "Deep Throat" donned a cloak, wielded a dagger and wore many faces.
He was, the smart-money wagered, Gen. Alexander Haig, President Nixon's chief of staff; or Henry Kissinger, then National Security Advisor; or former FBI chief, L. Patrick Gray.
After four years of study, an investigative journalism class at the University of Illinois concluded "Deep Throat" was Fred Fielding, deputy White House counsel.
No, said a poll this year in Editor and Publisher, he was Chief Justice William Rehnquist.
Another suspect was John Dean, the lawyer who turned on the president and who, argued until the 11th hour, that the mystery continues.
"There's no hard evidence offered whatsoever in this piece, no corroborating evidence, no inside information only Deep Throat would know," Dean told NBC News Tuesday afternoon.
Named for the porn film featuring Linda Lovelace, "Deep Throat" became in a town with few secrets, the ultimate anonymous source. He was described in the book, "All the President's Men" as a combat veteran who smoke and drank heavily and who loved to gossip.
With a red flag in a flower pot, Woodward reportedly summoned "Deep Throat." With marks in a newspaper, he summoned the two reporters, telling them to "follow the money," which led them to the Committee to Re-elect the President; and, eventually, to the White House itself.
Herb Klein was White House communications director then.
"I think [it was] the most important thing which brought him down," says Klein. "I think he felt that other presidents got away with a lot. The press was stronger against him, he had a Democratic Congress, and a wrong was committed."
It only changed history. Nixon, re-elected overwhelmingly, might have remained in office without "Deep Throat."
"He was able to put them on the trail of the truth to find out just exactly what was going on in this scandal," says presidential historian Robert Dallek.
Tuesday, Washington's favorite parlor game ended, with "Deep Throat" revealed, after three decades in the shadows.