On a sunny California morning in August 1999, Joan Felt, a busy college Spanish professor and single mother, was completing chores before leaving for class. She stopped when she heard an unexpected knock at the front door. Upon answering it, she was met by a courteous, 50-ish man, who introduced himself as a journalist from The Washington Post. He asked if he could see her father, W. Mark Felt, who lived with her in her suburban Santa Rosa home. The man said his name was Bob Woodward.

Woodward’s name did not register with Joan, and she assumed he was no different from a number of other reporters, who had called that week. This was, after all, the 25th anniversary of the resignation of President Richard Nixon, disgraced in the scandal known as Watergate, and hounded from office in 1974. The journalists had all been asking whether her father—the number-two man in the F.B.I. during the Watergate years—was “Deep Throat,” the legendary inside informant who, on the condition of anonymity, had systematically passed along clues about White House misdeeds to two young reporters. Joan figured that similar phone calls were probably being placed to a handful of other Deep Throat candidates.

These names, over the years, had become part of a parlor game among historians: Who in the top echelons of government had mustered the courage to leak secrets to the press? Who had sought to expose the Nixon administration’s conspiracy to obstruct justice through its massive campaign of political espionage and its subsequent cover-up? Who, indeed, had helped bring about the most serious constitutional crisis since the 1868 impeachment trial of Andrew Johnson—and, in the process, changed the fate of the nation?

Joan was suddenly curious. Unlike the others, this reporter had come by in person. What’s more, he claimed to be a friend of her father’s. Joan excused herself and spoke to her dad. He was 86 at the time, alert though clearly diminished by the years. Joan told him about the stranger at the door and was surprised when he readily agreed to see “Bob.”

She ushered him in, excused herself, and the two men talked for half an hour, Joan recalls. Then she invited them to join her for a drive to the market nearby. “Bob sat in the backseat,” she says. “I asked him about his life, his job. He said he’d been out here on the West Coast covering [Arizona senator] John McCain’s [presidential] campaign and was in Sacramento or Fresno”—four hours away—”and thought he’d stop by. He looked about my age. I thought, Gee, [he’s] attractive. Pleasant too. Too bad this guy isn’t single.”

Woodward and Felt waited in the car while Joan popped into the grocery store. On the way home, Joan remembers, Woodward asked her, “Would it be all right to take your dad to lunch and have a drink?” She agreed. And so, once back at the house, Woodward left to get his car.

Joan, always looking after her dad’s health, realized she should probably caution Woodward to limit her father to one or two drinks. Yet when she opened the front door, she could find neither the reporter nor his car. Puzzled, she decided to drive around the neighborhood, only to discover him outside the Felts’ subdivision, walking into a parking lot of a junior high school some eight blocks from the house. He was just about to enter a chauffeured limousine. Joan, however, was too polite to ask Woodward why he had chosen to park there. Or why, for that matter, he had come in a limo.