I’m a longtime fan of Paul Simon, so I was looking forward to Alex Gibney’s documentary about him, “In Restless Dreams: The Music Of Paul Simon.” It originally was streaming only on MGM+, a service I don’t subscribe to, but since Amazon owns MGM, I happily discovered that it’s available on Prime Video, too.

Gibney is arguably America’s best and most prolific documentarian not named Ken Burns. Among the projects he’s been responsible for: “Going Clear” (Scientology); “Agents Of Chaos” (Russia’s attack on the 2016 election); “Totally Under Control” (the COVID pandemic); “Enron: The Smartest Guys In The Room”; and “Mr. Dynamite” (James Brown).

“In Restless Dreams” is full of archival film and photos, and reaches back to Simon’s early teen years, when he first started writing music and partnering with school friend Art Garfunkel. The doc examines the highs and lows of that partnership, from their huge popularity to their ultimate professional separation. There’s one moment that really stood out. Sometime in the 1970s, Simon was asked by an interviewer about the songs Garfunkel wrote. Simon interrupted to say, “What do you mean? There were none. He didn’t write any. They were all mine.”

In another section, he explains that when he was asked to do a concert in Central Park in 1982, his solo career was already going well, but he didn’t want to perform only songs from that era. Then he thought maybe he’d do the first part solo and ask Garfunkel to join him for the second half, and immediately realized that would mean Paul Simon was opening for Simon & Garfunkel, which sounded like a bad idea. So Paul invited Artie to do the whole thing with him and a crowd of half a millon people showed up to watch them.

There was a moment in that concert that shook Simon. He was performing a new song he’d never done in public, “The Late Great Johnny Ace.” In it, he references that singer (who died from a self-inflicted gunshot in 1954), as well as John Lennon and John F. Kennedy, both of whom were assassinated. Simon was about halfway through when a crazed fan ran onto the stage, shouting, “I have to talk to you, Paul, I have to talk to you!” He was dragged away by security guys and Simon finished the song, but was understandably rattled.

There’s also an extended portion about Simon’s many appearances on “Saturday Night Live,” thanks to his close friendship with Lorne Michaels, who is heard in voiceover commenting on several parts of Simon’s life. The highlight of the “SNL” section is Simon dueting with George Harrison. Seeing it again, I wished the two had done an album of duets, or gone on tour together, or did an hourlong TV show in which they sang each other’s songs together.

“In Restless Dreams” also goes in depth on the “Graceland” album, which Simon recorded with South African artists at a time when there was a boycott in place against that country because of its horrible apartheid policies. Nonetheless, Simon traveled there, discovered new sounds being created by local musicians which inspired much of the sound of the album. He also toured with several of them and invited South African exiles Miriam Makeba and Hugh Masekela to join him, which they did.

I particularly enjoyed hearing Simon discuss working with Mike Nichols on the soundtrack of “The Graduate,” which was a huge success, and later expressing his disappointment that the 1980 movie he wrote, scored, and starred in, “One Trick Pony,” was a box office bomb (I really liked it, and explained why in this review).

As wonderful as those highlights were, I had two problems with “In Restless Dreams.”

The first is it runs three and a half hours across two parts (or verses, as they’re called in the titles). While I remain a Simon fan and recognize he’s had a remarkable career full of great songs and stories, there’s only so much we need to know. The primary element that takes up more time than it deserves is watching Simon in his Texas studio developing his latest album, “Seven Psalms,” which consists of one downbeat song after another which all sound the same. Like the tunes, those sequences are slow and hard to get through.

Despite those issues, I enjoyed “In Restless Dreams: The Music Of Paul Simon” enough to give it 7.5 out of 10. Now streaming on Prime Video.