It's another new month, meaning it's time for another edition of Three Easy Pieces, where I examine a particular subgenre of pop culture from its birth, through its development, and seeing where it stands today. Music is powerfully capable of reflecting the world's state of mind at any given moment. When combined with the all-seeing eye of film, the two art forms are an unstoppable force and, sometimes, retroactively providing profound time stamps of the human condition. This month, we're looking at zeitgeist-capturing music documentaries.

BIRTH: Gimme Shelter

Honorable mention: Woodstock, Don't Look Back, The Last Waltz

For some, the decision of where to start is a no-brainer: Woodstock. While Woodstock may be a joyous, singular movie about the purity of musical expression, Gimme Shelter may actually be the better film. The 1970 film documents the disastrous 1969 Altamont Free Concert, which notoriously featured the Hell's Angels working as security, and the fatal stabbing of Meredith Hunter, which the filmmakers miraculously caught on camera.

Gimme Shelter's loaded with fantastic performances from some of the biggest acts of the day, but the sense of unease and escalating chaos runs underneath every scene. Some credit the Altamont Free Concert with officially putting an end to the ‘60s, and a nail in the coffin of the free love and mutual understanding that the ‘60s strived for. One highlight is the Grateful Dead arriving via helicopter, immediately realizing something is dreadfully wrong, and promptly flying away. And the scene of the Rolling Stones hopelessly going through with their performance while the crowd is frenzied -- and death is only moments away -- is one that definitely sticks with you.

DEVELOPMENT: Heavy Metal Parking Lot

Honorable mention: The Decline of Western Civilization Part II, Hype!, Buena Vista Social Club

Easily the shortest of the movies being explored, here, is 1986's Heavy Metal Parking Lot. At 17 minutes, it truly feels like a strangely innocent time capsule. Filmed in the parking lot of a Judas Priest concert in Maryland, the short is immediately notable for how the subjects act on camera: made in the days before everyone was used to being filmed, before reality shows were such a prevalent medium, Heavy Metal Parking Lot shows these concertgoers as awkward, excited and utterly sincere.

Because it featured so much unlicensed music, the movie was initially not officially released; rather the movie became a cult classic, getting traded around as a bootleg and slowly gaining a reputation as a sort of rubbernecking ode to the simple joys of heavy metal fans, and as an eminently quotable look at the inherent oddness of fandoms.

TODAY: Shut Up and Play the Hits

Honorable mention: Amy, Dig!, The Devil and Daniel Johnston

Like The Last Waltz before it, 2012's Shut Up and Play the Hits documents the rapturous farewell performance of an unassuming band that somehow tapped into a generation. Also like The Last Waltz, Shut Up and Play the Hits lives under a cloud of sadness and resignation. But, while The Last Waltz's documentation of the band's final concert comes complete with bandleader Robbie Robertson explaining their decision to call it quits (essentially, being on the road so frequently is unbearable, and has taken the lives of many of music's greats), Shut Up and Play the Hits' document of LCD Soundsystem's farewell show is a little murkier.

Frontman James Murphy, in interstitial interviews with Chuck Klosterman, seems to have no concrete reason for wanting to end the band. Murphy floats different options -- that he feels useless as a middle-aged man in a young person's genre, that he wants to call it quits while they're on top, that he might want to lead a quiet life and open a café or some such nonsense -- but they ultimately seem like patches for the truth: that he's scared, that sometimes it's easier to retreat than to accept love and success, that the pressures of being creative in a world full of increasingly visible artists can be too much to take.

Whatever LCD Soundsystem's reasons for disbanding -- and subsequently reforming, it should be said -- Shut Up and Play the Hits is a film both about wonderful music and about the terror of leaving yourself so vulnerable to the public.

Three Easy Pieces will return, next month, with: Cartoons for Adults.