When she returned to the theater at 80, years after retiring from Parliament, it was — but of course — in the most titanically angry role in the classic canon: King Lear, at London’s Old Vic. The dazzled reviews, along with a slew of awards, testified that age had not mellowed or muted her. When she came back to Broadway, two years later, she gave an eye-scalding fireworks display as the splenetic, dying mother in “Three Tall Women,” for which she won a Tony.

In 2019, she did do Lear on Broadway, in a reconceived production tricked out with an abundance of postmodern conceits that might have smothered a less assertive star. Jackson cut through the surrounding flash like a buzz saw, throwing herself against the wall of old age and mortality until it seemed to crumble into unanswerable darkness.

Jackson was not given to self-analysis, or at least not in any way that she was willing to share with the world. Nor was she fond of discussing the details of her craft. And her life outside her work, she said, was simple — that of a grandmother who did her own shopping and cleaning in a basement apartment. She eschewed the trappings of 21st-century technology (no cellphone) and of celebrity, the fact of which seemed only to embarrass her.

And while she mostly avoided anything like personal confessions, she did make one admission that startled me. When I asked if it felt different performing for a live audience again, she said it felt exactly the same, meaning that this most fearless of dramatic actresses was profoundly scared. “You can go onto that stage every night,” she said, “and it’s always the equivalent of going onto the topmost diving board, and you don’t know if there’s any water in the pool.

“Every time I say, ‘Yes, I’ll do it,’ I think, ‘My God, I don’t know how to do it. I can’t do it.’ We are sadomasochists as well as being brave, actors, and we torment ourselves.”