One early assertion in Nick Broomfield’s new documentary appreciation “The Stones and Brian Jones” will stand out to many a Rolling Stones fan, the idea that “I don’t think many people remember who (Jones) was.”

Even someone coming to the Stones as a babe, late in the game, can hear the difference between the recordings the blues and blues-rock band the Stones made in the Brian Jones ’60s and the sound of the ’70s-onward stadium tour mainstays “The World’s Greatest Rock’n Roll Band” became.

Jones formed the band via classified ad, dove deep into the blues with them and was a big part of why they became wildly popular before Mick Jagger and Keith Richards ever wrote a pop hit with them. A stunningly-adept multi-instrumentalist, Stones fans recognize his musical coloration of “Ruby Tuesday” (recorder, flutes), “Street Fighting Man” and “Paint it Black” (sitar), “Under My Thumb” (marimba), “She’s a Rainbow” (Mellotron) and harmonica on many of their early blues releases as the hooks that made the songs distinct, memorable, and unlike anything the band released after his dismissal from the group.

But Broomfield, one of Britain’s great documentary filmmakers and no slouch at musical biographies (“Biggie & Tupac,””Kurt & Courtney”), delivers merely glancing assertions of Jones’ musical prowess — a jam session friend of Hendrix, pal of Dylan’s, sax man on a Beatles session and so forth. The Stones’ longtime bassist and curator of their history (a packrat who saw all and saved all) Bill Wyman is here, wide-eyed and delighted at playing back to Broomfield snippets of Jones’ genius and why he’s worth remembering.

Broomfield instead leans into his own specialty, charting Jones’ psychic path from glory to self destruction. His interview subjects note Jones’ sensitivity about his looks, his height, his “insecurities” which played out in legions of love affairs, including a long string of young British women the rocker hooked up with, whose families welcomed him in and became his support system after his estrangement from his own, five of them abandoned after he impregnated them and moved on.

The filmmaker interviews many of them, the most famous being the model/singer Zouzou and the legendary singer and Stones retinue queen Marianne Faithfull. And Broomfield has archival interviews with others, including the singularly-gorgeous and magnetically destructive Anita Pallenberg, whose betrayal came at the perfect moment to trigger Jones’ final descent into dysfunction — fired from the band — and his untimely death three weeks later back in 1969.

Broomfield tracks the erosion of Jones’ influence and “power” in the band and the way his bandmates noted how none of them handled their ascent into fame worse, or lost himself in drugs as deeply as Jones.

German filmmaker Volker Schlöndorff “(The Tin Drum), who filmed “A Degree of Murder,” starring Pallenberg and featuring a score composed and performed by Brian Jones, observes that “drugs destroyed his discipline,” and that “you can’t be an artist without discipline.”

Events certainly bore that out, as Jones became too unreliable for the band, and without the band’s demands, died within days of his not-unexpected dismissal.

Broomfield approaches this subject as a fan and an observer remembering the era he grew up in. He narrates the story, recalls meeting Jones on a train ride when Broomfield was just an impressionable 14 year-old. And a few years later, Broomfield was in Hyde Park, London, for the “farewell” concert the Stones gave just days after Brian’s death.

The film features extensive readings (by actor Freddie Fox) of Jones’ letters — to family, lovers, and his scores of revealing personal responses to band fan mail from those early years. The way he saw the band as “two bands,” the joy he got at exposing his blues heroes to the big wide (British) world bubbles through in these short hand-written notes.

Still, “The Stones and Brian Jones” doesn’t lend itself to the air of sadness and tragedy that hangs over Broomfield’s best known biographies — the musical ones, and his sympathetic portrait of serial killer Aieleen Wuornos. But it is essential viewing for any fan of ’60s music history and The Rolling Stones’ place in it, even for those of us who haven’t forgotten Brian Jones and his place in it.

Rating: unrated, profanity

Cast: Brian Jones, Bill Wyman, Zouzou, Marianne Faithfull, Lewis Jones, Michael Lindsay Hogg, Volker Schlöndorff, Mick Jagger, Keith Richards, Eric Burden, Charlie Watts and Nick Broomfield.

Credits: Directed by Nick Broomfield, scripted by Nick Broomfield and Marc Hoeferlin. A BBC Films/Magnolia release.

Running time: 1:37