Halfway through the hard-charging new rock documentary, "It Might Get Loud," [artist id="3108851"]Jimmy Page[/artist] throws on an old, crackling record, closes his eyes and starts jamming on an imaginary guitar. For a few seconds, despite his silvery ponytail and the fact that he was the lead guitarist for arguably the greatest rock band ever, the 65-year-old could be any kid in any bedroom, giving himself over to the pure pleasure of music. After all these years, all those stadium concerts and all those millions of albums sold, Led Zeppelin's Jimmy Page still plays the freakin' air guitar.

It is a sublime moment in a documentary filled with such rare glimpses into the private passions and public music of three generations' worth of venerated lead guitarists -- Jack White of the [artist id="610526"]White Stripes[/artist], the Edge of [artist id="1022"]U2[/artist] and Page -- each of whom have highly distinct -- and at times oppositional -- musical styles, yet share the same undying, irrepressible love for the electric guitar.

But that, as director Davis Guggenheim told MTV News during a recent interview, is the exactly the point of the documentary. "Every generation comes up in rebellion of the next generation," he said. "Led Zeppelin rebelled against these pretty-boy pop bands. U2 came up hating the big-hair stadium bands. And the White Stripes were saying, 'We don't like this overproduced, stadium-band sound.' A lot of times you express your rebelliousness with an electric guitar."

Somehow Guggenheim managed to corral these three guys into a warehouse for two days to chat and play together. Interspersed with this epic jam-session are the times when Guggenheim followed the artists around with a camera, getting them to tell stories about childhood epiphanies, professional struggles and the zig-zagging path toward rock stardom. We see White constructing a makeshift guitar out of a wooden plank and a Coke bottle, then wailing away as the cows on his Tennessee farm look on; the Edge visiting the school of his youth and pointing out the concrete slab on which U2 first performed as teenagers; and Page, who avoided any type of on-camera interview for decades but ends up giving Guggenheim a candid tour of the estate where Zeppelin recorded in the '70s and where drummer John Bonham overdosed at the age of 32.

How did the director pull this whole thing together, convincing these ego-heavy lead guitarists, in need of neither money nor exposure, to hang out with each other for a couple days -- to open up about what motivates them to write songs? Maybe it had something to do with Guggenheim's last documentary, "An Inconvenient Truth" -- an Oscar-winning investigation into global warming. (If you can make Al Gore look like a rock star as he heads through stadium corridors to deliver a PowerPoint slideshow, making actual rock stars look cool wouldn't be too much of a stretch.)But when it came to the camera-shy Page, it required something a little bit more.

"It took seduction," Guggenheim said. "It took us telling him how passionate we were about songs and songwriting, talking about the creative process."

The film, which opens on August 14, no doubt belongs in the upper echelon of rock documentaries, joining films like "The Last Waltz" and "Gimme Shelter," if only for the singular window it opens onto Page's life and work. Fifty years from now, if kids rocking their air guitars to Zeppelin tunes want to know what Page was really like, "Get Loud" will be their essential viewing.

And as Guggenheim explained, the connection between the past and the present, between old-school blues and classic rock, between punk and whatever comes next, will always be there. "The point of the movie is it could be anybody, any artist," he said. "It could be the next artist you haven't even heard of. It could be the guys from Blink-182. It really is the creative spark that you see in the movie. By looking back and seeing Jimmy Page and how he started and invented the dirty guitar sound, you can find that line all the way back through U2, through Jack White and now to the new guys who are doing it, like Green Day."

Check out everything we've got on "It Might Get Loud."

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