I have yet to read the book that this documentary is based on ("Chaos: The Truth Behind the Manson Murders" by Tom O'Neill and Dan Piepenbring. I believe the hardcover version was titled "Chaos: Charles Manson, the CIA, and the Secret History of the Sixties"). I've read several reviews of the book that go into the specifics O'Neill uncovered in greater detail than this documentary did. This documentary touches on some of what he found, but not all of it. O'Neill's book appears to be a much more thorough and truthful book on the subject than Bugliosi's Helter Skelter (O'Neill proves that Bugliosi purposely lied and left key facts out of his book). For a good introduction to O'Neill's book, check out Abby Aguirre's Substack post about it, or her excellent review "Down the Manson Rabbit Hole" in the LA Review of Books.
It's worth watching if the subject interests you, but from the reviews I've read the book sounds much more comprehensive. The documentary has some interesting interviews with one of the prosecutors, some Manson family members, and O'Neill himself. It brings up some of the questions found in the book, such why did Manson's parole officer continue to insist that Manson was doing great when meanwhile he was arrested repeatedly (and not locked up for violating his parole)? Why have Manson's complete parole records never been released? Why were his parole files not permitted as evidence in his trial?
I feel the documentary could have been edited better and should have been longer and included more of the details from the book, but it is still interesting for people who want to learn more about this subject.