“We want things a certain way, and we’re going to have it,” says a self-possessed and zonked-out Donovan near the end of “All My Loving,” Tony Palmer’s 1968 documentary about the nascent pop movement and its startling grip on the youth of the period. “The pop music is changing the whole scene. Fashion will change, architecture will change, eating, everything.”

For those who were watching when the film made its television debut on the BBC 39 years ago, this young folk singer’s arrogance might have seemed laughable. But the 50 minutes of Mr. Palmer’s film preceding Donovan’s remarks and the confidence with which he utters them suggest that the burgeoning psychedelic movement was no laughing matter. If these kids — the children of survivors of war and economic catastrophe — were as ambitious as they were idealistic, if their devotion to getting wasted paralleled their devotion to social upheaval, the world was in for a long, strange trip.

Mr. Palmer, at the time a veteran of classical music documentaries who would go on to direct some of cinema’s pioneering “rockumentaries,” was presciently aware that pop music and all the commotion that came with it was not simply the harmless entertainment of the maturing “me” generation. His narration in “All My Loving,” which will be released for the first time on DVD next week after making a one-night appearance tomorrow at the Pioneer Two Boots Theater, balances an admiration for and fear of his subjects. Think about how the late Steve Irwin would have described crocodiles if they suddenly decided to take over the world — and it looked as though they actually might.

It is that mystery, the idea that this movement was as powerful as it claimed to be and that its ultimate effect was frighteningly unpredictable, that affords “All My Loving” its power and makes it a priceless historical document. As Mr. Palmer intercuts clips of the Animals performing their cheeky ode to hedonism “Good Times” with footage of riotous youngsters clashing with police in the London streets, it is clear he has every intention of scaring his audience. Why he wants to scare them is less clear, though his use of a surrealistic visual style — jagged cuts between seemingly unrelated images, footage of devastating brutality emerging from Vietnam, the dubbing of piercing screams over concert footage of Cream, Jimi Hendrix, and the Who (not that the sight of Pete Townshend viciously beating his own guitar was wanting for shock value) — suggests that he was smitten with the aesthetics of the psychedelic movement.

But it is also clear that he reveled in his role as prophet, grabbing hold of the burgeoning underground and pulling himself up onto a teetering soapbox. “Everyone demands the existence of heroes,” he announces. “Heroes who can be worshipped — be they gods, generals, lone yachtsmen, television personalities, cultural leaders, or pop stars.” Then he concludes his declaration with evidence, for anyone watching 40 years later, that it didn’t take a weatherman to know which way the wind was blowing. “In this time of instant global communication, these heroes can become monsters.”

But the musicians interviewed here are monsters only in terms of their talent. Apart from that, they’re mostly well-meaning kids with a bullhorn, a pocketful of drugs, and an increasingly suggestible following. The real gems to be mined from the film fall from the lips of 25-year-old elder statesmen like Paul McCartney and Mr. Townshend. If for no other reason, “All My Loving” is essential for capturing the men who would define their generation just as they realized they were doing it. Mr. McCartney, who was busy writing the “White Album” when not sitting down for Mr. Palmer, speaks of his newfound power like a comic book hero who has just discovered his super-human strength.

The question on everyone’s mind, especially his, is what will become of it. “We could have thought, ‘Let’s use this for evil,’ But there’s no desire in any of our heads to take over the world,” he says of the Beatles, who seemed suddenly to have the option. “That was Hitler, that’s what he wanted to do.” And just as he utters the name of the man who nearly destroyed Britain only 25 years before, a reflexive grin creeps across his face, as if he knows and still cannot believe that he just might be as powerful. Ob-la-di, Ob-la-da.