But then things got weirder.

When production on this unnamed ''Metallica infomercial project'' began in 2001, the group was already mired in turmoil: Newsted had officially quit the band after only one session with Towle. Newsted still considers the idea of rock-band therapy to be a little ridiculous. ''Something that's really important to note -- and this isn't pointed at anyone -- is something I knew long before I met James Hetfield or anyone else,'' Newsted said in an interview from his ranch in western Montana. ''Certain people are made to be opened up and exposed. Certain people are not. I'll leave it at that.''

For the first 30 minutes of ''Some Kind of Monster'' (roughly three months in real time), you see a band whose members don't necessarily like one another, struggling with a record no one seems completely enthusiastic about creating. But then -- suddenly, and without much explanation -- Hetfield disappears into rehab. Ulrich and Hammett have nothing to do in the interim except talk to their therapist. This is the point where ''Some Kind of Monster'' starts to change; what it becomes is not a glorification of rock 'n' roll but an illustration of how rock 'n' roll manufactures a reality that's almost guaranteed to make people incomplete. Metallica's massive success -- and the means through which they achieved it -- meant they never had to mature intellectually past the age of 19.

''I think most people in rock bands have arrested development,'' Hammett says now. ''Society doesn't demand people in rock bands do certain things. You're able to start drinking whenever you want, and you can play shows drunk, and you can get offstage and continue to be drunk, and people love it. They toast their glasses to an artist who's drunk and breaking things and screaming and wrestling in the middle of a restaurant. Things like that happened to us, and people cheered.''

To some, that might sound like a cliché sentiment for a millionaire musician to express. It almost blames society for making guitar heroes wasted and lawless. But this kind of self-discovery is part of what makes ''Some Kind of Monster'' a strikingly modern film: by fusing the accelerated culture of therapy with the accelerated culture of celebrity, it illustrates why the people inside those two realms can't keep up.

''Metallica's evolution as people was aborted by their surreal existence,'' Towle says. ''Kirk Hammett once told me that coming off tour was like experiencing post-traumatic stress syndrome; he said it was like leaving a war and re-entering real life. When I asked him why he felt that way, he said, 'Because now I have to empty the trash.' The profundity in that statement is in its simplicity: rock stars are infantilized by people who do everything for them. We insulate them from a reality that would actually be good for them.''

This unreality does not apply only to drinking and garbage removal either. That becomes especially clear when Hetfield returns to the band from rehab as a completely changed man. Slowly, the deeper issue of ''Some Kind of Monster'' emerges: Hetfield and Ulrich have spent their entire adulthood intertwined, but they've never been close; they've never needed to have a real relationship with each other. And that is what you mostly see over the last hour of this film: two middle-aged men fighting through their neuroses and confusion, earnestly talking about intimacy and emotional betrayal and how they feel about each other.

It is important to remember that these two men wrote a song called ''Seek and Destroy.''

Why Metallica allowed Berlinger and Sinofsky to film this process remains baffling. ''Lars felt the therapy sessions were actually enabled by the presence of the cameras,'' Berlinger says. ''He felt the cameras forced them to be honest.'' There's certainly no question about how much the band believes in this film: when Elektra Records grew concerned over the project's escalating cost, the label considered turning it into a reality TV show. By that point, both the filmmakers and the group saw this solely as a theatrical release. They wanted complete control, so they bought the rights. Which means Metallica wrote Elektra a check -- for $4.3 million.