I'm Not There is a Bob Dylan biopic in the same sense that his Chronicles amount to an autobiography. It's a portrait, certainly, and perhaps most of the story of his life is in there somewhere, but it's really not about the narrative.

Like the book, and the songs, and the man himself, the film is self-consciously fragmented, and if there is any overall coherence it is buried beneath the surface. What we get instead is poetry, posturing, vivid impressions and catching emotions, truth told mainly in the wide arc being danced around it. When it works, it's as beautiful and honest and moving as anything America's ever produced. When it misses the mark, it leaves you baffled and wondering if wasting your time was really the intention, or maybe it's you who is missing the point.

In many ways the films an amazing achievement. Almost all of the actors playing facets of the man put in great performances; it would have been hard to believe that a bullshitting thirteen-year-old black kid and a willowy blonde woman in a wig could ever bear such an uncanny resemblance to the grizzled Jewish singer, and many scenes from his life are enacted pitch-perfectly and paced with style.

The film owes a great debt to Scorsese's excellent No Direction Home, both in the tropes it borrows and the stories it tells - but of course, where Scorsese was limited to interviews and archive footage, Todd Haynes dramatises freely. We get to witness the reaction of the crowd to Dylan's too-loud electric set at a folk festival, watch Pete Seeger grab a fire-axe to cut the power to the amps only to be restrained just in time.

The soundtrack is a gift to Dylan fans - and if you're not at least a latent Dylan fan, I'm afraid this probably isn't this film is for you. We are treated to a collection of many, many of his best songs, a mix of his original recordings and consistently good cover versions. Marcus Carl Franklin, the extremely talented little black kid who claims to be Woody Guthrie in the film, appears on the soundtrack with his own versions of the songs he sings. He is the only actor to do so, though Christian Bale in particular has been said to be a pretty good singer. Elsewhere we have original Dylan recordings as background music, or illustrating the narrative. One dramatic, dream-like sequence is essentially a music video for Steven Malkmus' extended version of Ballad of a Thin Man. It works very well. The official sountrack album apparently consists mostly of songs that aren't in the film itself, and leaves off all but one of the original Dylan tracks - a strange way of doing it, but I guess it's quite in keeping with the whole approach of I'm Not There.

The film is far from flawless. For my money it's at least half an hour too long, and the entire Richard Gere/Billy the Kid segment of the film did nothing for me. Was it there as a reminder that Dylan at his very worst is rambling, pretentious and impenetrable? Is that a valid artistic point to be making? Whatever, it's lost on me, and Gere's also the only actor in the film who totally fails to convince as Dylan - although Heath Ledger's performance works best if you bear in mind that he's technically playing an actor playing the singer. For all its faults, it is mostly a truly excellent film; if you're interested in Dylan at all, I'm Not There is well worth experiencing.