You don't have to be a Beatles fanatic to enjoy this documentary, but it helps. Paul McCartney joins legendary producer Rick Rubin in a large studio and goes through various Beatles songs, albums, memories, as well as moments from the Wings and his solo career, in non-chronological order. The format is simple - and filmed in black and white. Rubin asks McCartney a leading question or plays a bit of a classic song through a mixer (sometimes removing the instrumentation so you only hear McCartney's voice, or removing the voices so you only hear the instrumentation). And then he just lets Sir Paul talk. And we're talking the Beatles here so there are many fascinating stories to be told.
Rubin also has access to original tracks from Abbey Road so you hear previously unreleased versions of many classic tracks. For someone who is credited for bringing rap music and hip hop into the mainstream, Rubin is a certified music historian for all genres, and McCartney is totally at ease with him and even feels humbled by his role as the interviewer.
Some viewers who just want to hear music without all the "background" may get bored with the documentary. The documentary is 3 hours long, but is presented in 30-minute episodes. The recent Bee Gees documentary directed by Frank Marshall would have benefited from this approach.
As these legendary musicians are entering their twilight years (but McCartney amazingly is still putting out albums of good to great material), it is critical to get these documentaries made now. I would love to see a similar documentary on Bob Dylan. I tried to get into the various documentaries on Dylan and couldn't. This simple, stripped down approach in McCartney 3, 2, 1 should be a new template for other music documentarians.