“When you slip on a banana peel,” Nora Ephron liked to say, “people laugh at you. But when you tell people you slipped on a banana peel, it’s your laugh.”

This was a guiding principle of her life: power, via sharing. Control, via opening up. You tell the story, so the story doesn’t tell you. Banana-peel logic informs another Ephronism, the one that gives its name to the documentary about Ephron’s life that is currently airing on HBO: “Everything is copy.” The line comes from Ephron’s mother, who—like pretty much everyone else in her family, including both of her parents, all three of her sisters, all three of her husbands, and one of her two sons—was also a professional writer. And it’s a fitting motto for Ephron, who, on top of everything else she accomplished, anticipated the searing, first-person confessional that would become one of the defining modes of Internet writing.

“Writers are cannibals,” Ephron told Charlie Rose in a long-ago interview. “They really are. They are predators, and if you are friends with them, and if you say anything funny at dinner, or if anything good happens to you, you are in big trouble.”

Everything Is Copy was created by Ephron’s son, Jacob Bernstein (the son who is a professional journalist) as an act of tribute, and questioning, and sense-making. And the documentary is—as Ephron herself was, it suggests—witty and generous and occasionally brutal in its honesty. Through interviews with Ephron’s many famous friends and colleagues (Tom Hanks, Rita Wilson, Steven Spielberg, Gay Talese, Rosie O’Donnell, Meg Ryan, Mike Nichols, and on and on) Bernstein presents his mother as a writer who lived out loud, insistently. The film is composed of the two layers that most good writing involves, somehow: declaration and exploration, with the one animating the other.

The “declaration” aspect is clear enough: Everything Is Copy presents the many ways in which Ephron made good on her word, through words. She relied, professionally and personally, on the alchemy of the anecdote. She transformed her experiences—the good and especially the bad, the big and especially the small—into stories. Through her early essays in Esquire, through her novel, through her later essays and plays and screenplays, she wrote about family, and friendship, and motherhood, and womanhood. She grieved her divorce from Carl Bernstein, and in some sense got revenge for it (she’d caught him cheating on her while she was pregnant with their second son) by writing a thinly veiled novel about the experience. She wrote about finding love again. She wrote about being betrayed by our culture’s optimism about romance; she wrote about being redeemed by it. She wrote about fake orgasms, and fake breasts, and the various indignities heaped upon women for the crime of failing to die young. She wrote about her neck. She wrote about her sons. She wrote about pie.

Ephron was the consummate “over-sharer,” using her copious capacity for honesty—“I feel like her allegiance to language was sometimes stronger than her allegiance to someone’s feelings,” Meg Ryan puts it—to exert control over others, and over herself. (Bernstein postulates that his mother’s “control freak” tendencies might have had to do with the fact that both of her parents became, late in their lives, alcoholics: She sought the control that their own lives failed to afford.)

But all of that is the “declaration”: She told the stories so the stories wouldn’t tell her. The “exploration,” though, is more interesting. And it has to do with the one time in Ephron’s life when she violated her own edict: her refusal to write about, and indeed even to talk about, the illness that would, in 2012, take her life. That she was sick—during the filming of Julie & Julia, during the production of the Ephron-written and Tom Hanks-starring Broadway play Lucky Guy—was a secret she kept from all but her closest family members. (“It was very hard,” Meryl Streep, who shot Julie & Julia with Ephron during her illness, tells Bernstein of being kept in the dark. “Because it was an ambush.”)

So: Why?, Bernstein—on behalf of Ephron’s family and friends and fans—asks in the film. Why did the woman who spent her life so ardently and wittily refusing to acknowledge the “T” in “TMI” finally decide to clam up? Why did this most public of people end her life so fiercely guarding her privacy?

The answer, Bernstein postulates, comes back to the banana peel: Ephron’s need to control the story. Coupled with, perhaps, her recognition that “control,” life being what it is, is largely a lie. “I think at the end of my mom’s life she believed that everything is not copy,” Bernstein concludes—“that the things you want to keep are not copy, that the people you love are not copy, that what is copy is the stuff you’ve lost, the stuff you’re willing to give away, the things that have been taken from you.”

In that sense, for someone who saw storytelling not just as a vehicle of human connection, but of control, it follows that the one thing that so cruelly deprives a person of both—death—would be the exception that proves the rule. “Once she became ill,” Bernstein writes, “the means of controlling the story became to make it not exist.”

This was another way, in the end, that Ephron anticipated the culture of the moment—one that embraces radical transparency, aided by social media, but that also recognizes limitations to that transparency. We live in a world—all that posting and Instagramming and Snapping and sexting—that would seem to believe, like Ephron, that everything is copy. And yet it’s a world that also acknowledges limits to that belief. Some things can’t be ‘grammed. Some things are bigger than a status update.

Everything Is Copy, its title notwithstanding, recognizes that fact. It advocates, in the end, for strategic privacy: for acts and experiences that are made all the more meaningful because they are not shared—except, perhaps, with those who are closest to us. That Ephron kept her biggest secret for so long was one more way in which she translated her personal experience into a broader cultural truth. “She’s the one who said, ‘There is no privacy,’” Meryl Streep recalls in the film, still grappling with the shock of Ephron’s death. “‘Forget privacy, it’s gone.’ And this is the most fascinating thing in the world to me, because she achieved a private act in a world where the most superficial parts of the most intimate acts are everywhere.”

The overarching irony of the film, of course, is that it is Ephron’s son who is reversing that intimacy, who is exposing his mother’s long-guarded secret—guided, it seems, by the very instinct his mother gave to him, and that her mother gave to her. Ephron ceded the control to her son, not just because because death robbed her of the ability to say otherwise, but because she seems to have recognized, in the end, the other power that comes from sharing: love. Ephron spent her life slipping on banana peels, maybe, but she also spent much of it loving her son. Now, he is turning that love into stories. And weaving those stories into her legacy.