So shortly after I read Linda Ronstadt's "musical memoir", Mrs. Salad and I drove down to Portsmouth to see this new documentary covering roughly the same topic at the Music Hall.
What can I say? I've been a Linda fanboy for decades.
If you want to choose only one, though, I'd recommend the movie. In addition to Linda's narration*, there are a bunch of famous talking heads: Ry Cooder, Peter Asher, Bonnie Raitt, Dolly Parton, Emmylou Harris, … So we get multiple viewpoints, always a good thing. But the same lesson shines through both book and movie: Linda was primarily about her music, not so much her career. (Ry Cooder makes this point explicitly.) She could have been content with her career niche: pop/rock goddess, singer of oldies and ballads. Instead she went to projects that interested her: old American standards, Mexican songs, operetta, vocal partnerships with singers she admired.
When I read the book, I noticed that her $500K gig at Sun City, in apartheid South Africa, was totally missing. That's briefly covered here in archival footage of an interviewer asking about it, and her self-defense.
You'll hear something about Jerry Brown in both book and movie. You will hear about George Lucas and Jim Carrey in neither.
There's a bittersweet ending to the film: 2019 footage showing Linda singing along with her nephew Peter and cousin Bobby. Well, sort of singing. Parkinson's disease has weakened her singing voice. (Although I'd bet she can still sing better than 99% of American citizens.)
Oh, yeah: Peter Asher kind of looks like Yoda these days.
* Given her illness, I don't know if she actually does the narration. It's someone who sounds like her, anyway, speaking in first-person singular.