Who would’ve guessed that the key to the already legendary series, “The Sopranos,” lies firmly embedded within the dysfunctional relationship between the show’s creator and his mother?

I’ve decided not to give away much at all. But here’s a brief outline of this excellent documentary:

In famed documentarian Alex Gibney’s new two-part film, it is David Chase and his late mother upon whom so much of the story of Tony Soprano (James Gandolfini) is based. But not solely; we learn that Chase was a workaday TV director and writer early on and was already something of a veteran when his hit TV show was finally born.

In the exhaustive retrospective, it’s all about Chase at first – a somewhat enigmatic man who, at one point, questions the wisdom of his lengthy bio-confessional. But don’t worry, fans; most of the big characters, the actors,  get their turn in front of the prying camera- each having notable backstories that preceded the best jobs they’ll ever have (notable exception: Steven Van Zant, Springsteen’s lifelong pal and the de facto musical director of the E Street Band).

It’s really a doc for the dedicated viewer who appreciates the minutiae of it all. Why was this location used for that scene? Why did Gandolfini disappear for days from the set? Did the Soprano family die or finish their grub at the Diner in the series finale? Well, maybe not all of your questions will be answered, but most will.

Of course, Gandolfini had long since passed away before the making of this film, so Gibney relies on archival footage and the words of his loving castmates to fill in his part.

Will folks who’ve never seen an episode of the series care about this doc? Honestly, probably not. It really is something of a giant Easter egg for the faithful-a reward for the loyalists. I kept thinking of my friend Jason (from New Jersey, of course) who I imagine will have only one “I didn’t know that” for every dozen, “I knew that” s, but it is he who Gibney is gifting David Chase’s thorough introspection.

You can see Wise Guy: David Chase and The Sopranos on HBO and streaming on Max.