Cameron heard about Elliot’s death in the newsroom of The Hollywood Reporter, where she was working at the time: “I kicked into professional mode and said, no one else is going to write that obit. I’m going to do it.” She tracked down Carr by phone in Nilsson’s apartment. “He could barely speak,” Cameron recalled. She asked what happened, and he said he didn’t know. “‘Oh, wait,’” she recalled him saying. “‘I see a half-eaten ham sandwich on the night stand. That’s good. You tell everybody that she choked on a ham sandwich, do you understand me?’”

“And I did it,” she added, “because I wanted to protect Cass.”

What was she protecting her from? “I was not aware of a lot of drugs,” she said. “I just wasn’t one of those people. And I had some suspicion around the time that she was going to London that she was on some sort of pills, but I didn’t really know anything.” In a split second, Carr and Cameron decided there was less shame in a woman ridiculed for her weight choking to death than there was in her having a drug problem. “What a terrible thing,” Cameron said, “but I was in too much of a state of shock to clean it up.”

She, too, is confounded by the story’s persistence. “Of all of the things I’ve done,” she said, “this ham sandwich has followed me my entire life.”

That story had long haunted Elliot-Kugell, too, though she felt some closure after Cameron privately divulged its origins to her when they met for lunch in 2000. Elliot-Kugell is cleareyed about what probably caused her mother’s death: “I mean, look. She was up for 48 hours, and she was at a party. Do the math.” But she doesn’t want to dwell on that. “The thing that was really important for me was that I didn’t want to write a salacious book,” she said.

In some sense, any memoir by a child of the Mamas & the Papas exists in the shadow of Mackenzie Phillips’s 2009 bombshell, “High on Arrival,” in which she accused her father John Phillips of sexual assault. But Elliot-Kugell’s memoir belongs on a different shelf entirely. It is a humanizing portrait of a woman whose legacy has, for far too long, been reduced to an outdated urban legend.

And it is a tale of an imperfect mother and a grieving daughter, of loss and long delayed catharsis. A few weeks before we spoke, Elliot-Kugell went to visit her mother’s grave. “It’s always weird when I go there, because I never know what to say,” she said. “But that day felt a little different because when I went up to the grave, I just said, ‘Hi.’ Like the way I would greet one of my cousins, or somebody who I know really well who I haven’t seen in a while.”

“I thought to myself, ‘Why, why why does it feel like this?’” she said.” All at once it dawned on her: “After going through this experience, I feel closer to her.”