The Muppets, taken in the broadest sense, predate by a considerable margin the 1976 debut of The Muppet Show, (Kermit the Frog himself first appeared all the way back in 1955) but it was with that marvelously off-kilter parody of/homage to the ossified traditions of vaudeville and the variety show that Jim Henson's ingenious puppetry rose from the ghetto of children's entertainment (although it can be easily argued that Sesame Street is the finest children's entertainment of all time and not least because of the special Muppets created for that show) to the level of national obsession. Henson's desire to experiment with narrative forms probably made a leap to feature films an inevitability, and the show's popularity just sealed it; thus it was that at the end of the show's third season (of five), that he gave to the world the evocatively-titled The Muppet Movie, which is, with all due respect to a great television program, the quintessential Muppet project, and almost certainly the most condensed and purified expression of the starry-eyed optimistic humanism that defined all of Henson's best work.

The film begins with a characteristically postmodern gesture: the Muppet are gathering in a studio screening room to watch the movie they just made about themselves. On one hand, this is an excuse to get characters onscreen who wouldn't have fit into the film's proper narrative; but it's also an extension of The Muppet Show's self-referentiality (a variety show about putting on a variety show) and a way of reinforcing the "realness" of the Muppet characters outside of the fictive universe of the movie, and a quick way of putting us, in the audience, in the best possible headspace to appreciate the silly playfulness of the whole movie.

"Is this how the Muppets really got started?" asks Robin (Jerry Nelson), the cutest and most heartbreakingly innocent of all Muppets. "Sort of approximately", responds his uncle Kermit (Henson), and that quip hides a fair kernel of truth, which is that The Muppet Movie, while it obviously does not tell anything resembling a true story, is autobiographical in the sense that Kermit's own journey through the film is more than a little similar to his creator and alter-ego's drive to be an entertainer. Early on, Kermit is sitting in the swamp, strumming his banjo (and singing the luminous song "Rainbow Connection"), when a visiting Hollywood agent paddles by in a boat, looking for the way back to human civilisation; this agent points out a "Frogs Wanted" audition ad in Variety, and sends Kermit on a trip to become a star not out of a desire for fame and money, but by an appeal to his good nature. Kermit, he claims, could make thousands of people happy, and it's that possibility - the sense that he might be able to make the world itself a better place through making people feel better - is what gets the travelogue started, and along the way, Kermit picks up all the familiar faces that make up the Muppet roster - Fozzie Bear and Miss Piggy (both Frank Oz), The Great Gonzo (David Goelz), Rowlf the piano-playing dog (Henson once more), the giant monster with a dear soul, Sweetums (Richard Hunt); and while Kermit is frequently unnerved by the growing size of his entourage, he takes on all of them in the feeling that the more friends he can bring along, the more those friends will be as happy as he is. By all accounts, it's a similar motivation that animated Henson himself, and it doesn't take the encomiums of his presumably-biased collaborators and family members to see how that's the case; it just takes looking at what he made. Nobody could have created and produced Fraggle Rock who was not passionately concerned with leaving humanity better than he found it.

And so there is this sentimental, tender strain that courses all through the movie, coming to the fore in some of the music and scenes (especially a moment late in the film where Kermit, alone in the desert, steels himself up to keep plugging along even though by this point everything looks hopeless), and it is this spirit of goodwill that is the reason The Muppet Movie is the pinnacle of Muppet art, in my considered opinion (only The Muppet Christmas Carol, made after Henson's death and at least partially as a tribute to his life, comes close to matching it). More to the point, it's this tenderness, when paired with the the sharp wit and barbarically awful puns that were the hallmark of The Muppet Show, that elevates the movie to such a height: it is the perfect combination of sweet and salty, whether in the characters and their emotions, the jokes, or the mix of songs - while "Rainbow Connection" always dominates any discussion of the film's soundtrack, all of the songs by Paul Williams and Kenny Ascher are top-notch, and there are three I'd put right up there with the better-known theme song: the comic duet "Movin' Right Along", the acerbic love ballad "I Hope That Somethin' Better Comes Along", and the subdued, childlike ode to dreams and the future, "I'm Going to Go Back There Someday".

It's the comedy that people remember best, I think, which is fair: the comedy is excellent, a scattershot catch-all of different comic styles written by Henson's longtime collaborator Jerry Juhl and Muppet newbie Jack Burns; the film is stuffed to the bursting point with impeccably timed cameos from people like Dom DeLuise, Steve Martin, and Madeline Kahn, all the way up to Orson Welles delivering a single line with a hilarious gravitas that no-one else could have mustered; as the film's sole important human, Charles Durning is a sheer delight as the good ol' boy fried frogs' legs restaurateur, hunting Kermit to be his new spokesman. The Muppet performances are all a great deal of fun, with career-best work in some cases: Henson's best performance of Kermit, Frank Oz's best Fozzie Bear (though not his best Miss Piggy), the best use of the post-'60s rockers of Electric Mayhem ever. And the vastly expanded budget of a feature allows for a lot more invention with how the Muppets are used, including a scene of Kermit riding a bike that was as sophisticated as any animatronic work in film to that point.

The only thing holding The Muppet Movie back from being a masterpiece- no, strike that, The Muppet Movie is a masterpiece, one of the best movies of 1979, the best original movie musical of the 1970s, and one of the all-time great family comedies. But it could be better, if not for one thing: the director, James Frawley, a man with a bit of TV experience, very little experience with feature films, and none at all with the Muppets. There is a palpable discomfort with what to do about the camera in nearly every moment of the whole movie: shots go on for too long, the blocking is uncomfortable and the Muppets all have too much headspace most of the time (the art of framing a shot so that both people and Muppets fit in it without it screaming "THE FROG IS A HAND PUPPET!" is a subtle one, perfected in years on the show). Luckily, the performers all knew their work well enough that Frawley wasn't able to do any serious damage to a great script and better characters, but his consistently tentative, flat handling of the film is a constant, low irritation, like a slightly-too-big fleck of stone in your sock. By all means, The Muppet Movie that we have today is a great thing, but it's just possible to imagine an even better and more perfect one; I am anyways not surprised that the next Muppet feature was directed by no less a Muppet expert than Jim Henson himself.