In his short and tortured life Kurt Cobain attempted suicide at least three times: a pill-and-champagne overdose that put him in a coma in Rome, the shotgun blast that did him in a month later, and, unbeknownst to anyone, a first attempt when he was 15 years old. After being publicly humiliated at school over a girl, he went out alone in the middle of the night to a run of parallel train tracks near his hometown of Aberdeen, WA, and lay down, weighted with concrete blocks, waiting for the approaching freight train to cut him in two. The only thing sparing the life of the man who would be lauded as "the voice of the grunge generation" and an inestimable contributor to the history of American music was that he guessed wrong about which track the train was traveling on. We only know that story because Cobain recorded it on a private cassette tape, one of hundreds in an archive of recordings, drawings, journals, and videos turned over to documentarian Brett Morgen, who, with the blessing of Cobain's widow Courtney Love and daughter Frances Bean Cobain, spun this unseen treasure trove into Kurt Cobain: Montage of Heck, a poignant, profound, unflinching and heartrending portrait that scratches away our own mythologizing of an icon to reveal how a person goes from the happy, tow-headed toddler seen in early home movies to a shotgunned corpse in only 27 years. It's not a path connected in a straight line. There were lots of breaks in the bone along the way: the heartbreak of his parent's divorce, a hyperactive temperament, a chronic stomach ailment, an unhealthy reliance on self-medication for all his physical and emotional pains, and -- perhaps the hardest burden of all -- a ceaseless ambition to be an accomplished artist of uncompromising integrity, as defined as a refusal to bow to any force or power that would ask him to be anything other than exactly who he was. Morgen makes these challenges real through the innovative tactic of animating the copious drawings and scribblings in Cobain's journals, so that they quicken again with their creator's intent. When there's no visual record to draw from, he uses rotoscoped reenactments, a la Waking Life, synced to Cobain's audio diaries and sound-collage experiments to reconstruct events from his pre-fame life. He also interviews only a few choice survivors: only some family members, only one ex-girlfriend, only one bandmate, and of course Courtney Love, whose exuberant, uninhibited interactions with Cobain in home videos paint a very different picture of an equal, loving partnership between two lost souls grateful for each other's love. It's agonizing to watch both of them poised on the edge of a domestic life that could have brought them both peace, knowing Cobain was in a race against his own pain, and his pain had more gas in the tank. So few biographies manage the trick of simultaneously being an anatomy of a tragedy and a celebration of a person, of exposing the deepest core of someone already flayed by the public gaze without further debasing them. Even though Montage of Heck is achingly intimate, it never feels like a violation. It's one of the best rock documentaries ever made, but its audience is broader than just music fans. It's for anyone who loved someone who got tangled in an era they couldn't endure, and what happens when they decide to stay behind.