The uniquely funky one-man-band filmmaker Ross McElwee is really more of a essayist than a director. So it's no surprise that his new work opens with the humble literary device known as the byline. Under the title "Bright Leaves," it merely says, "by Ross McElwee." And that's all. It might have read "A Ross McElwee Film" or even "A Ross McElwee 'Smokin' Epiphanies' Production, Written, Produced, Edited by Ross McElwee, From a Story by Ross McElwee, Suggested by Mr. McElwee's Twisted Family History as Intertwined With the Devil Weed Tobacco," or some such.

This modesty not only serves McElwee well, it is the core of his method. His films are not by nature bombastic, egotistical, self-mythologizing or even routinely self-important, as have been the case with so many recent "documentaries." He has a sly and often self-deprecating wit and a willingness to confront emotional and historical complexities without resorting to cant, agitprop or simplification. The results are brilliantly amusing; this is a movie that doesn't make you feel stupid on the way out or like someone has been spraying you in the face while making his talking points.

McElwee, who is North Carolina-born (his best known film -- 1986's "Sherman's March" -- was, more or less, about Civil War history), begins his trek into, more or less, family history and lost opportunities and found regrets with the sensuous image of lush, broad green leaves undulating in the sun under an ever-so-slight breeze. They shimmer, they slide, they slither, tethered by their stems, seductive and frightening at once. They are of course tobacco leaves, green killers and greenback manufacturers at once, and while this image holds the screen, in his reedy fifty-something voice, McElwee (off-screen as he is almost always, except in the occasional reflection or long shot) confesses that, living in the murky North, he misses the sunny South. The chance to go home again comes when a cousin contacts him with Important Family News on the tobacco front.

The cousin, a movie memorabilia collector, has one of the few extant prints of a long-forgot Michael Curtiz romantic melodrama from 1950. It's "Bright Leaf," with Gary Cooper as the heroic Brant Royle, inventor of the cigarette. Hard to believe, but such a film was actually made in those pre-surgeon general's report days. (I've even seen it!) Anyhow, the cousin thinks that the film, based on a novel, might be about an early McElwee, the great-grandfather of them all, who made and lost a fortune in the tobacco business and was ultimately beaten at the cancer stick game by Buck Duke, he of the famous fortune, family and university.

On this slender possibility does McElwee launch himself on another improbable odyssey across the New South in search of the Old South, and through his own psyche in search of clues to who he is and why he is that way. But his method has always been discursive rather than cumulative; he widens, even drifts, rather than narrows and defines. If it amuses him, he throws it in. He is too witty an observer of the scene not to stop for a particularly engaging riff on anything that particularly captures his imagination -- beauty queens, for example, in an age of political correctness when everybody gets to be a princess. Or the pleasures of filming garbage cans and motel parking lots. Or the life stories of people who live on lands that used to be tobacco fields. Almost always, McElwee believes that the folks he runs into are more interesting than he is. He gives them ample time and if he didn't have such a good eye, the film would seem to last a few ice ages or so. But the thing just sings along.

At some point, of course, he must return to self and family. His great-grandfather, who once was wealthy enough to build a North Carolina mansion complete with subsidiary dwellings called "The Children's Homes," ended up a bankrupt, embittered outcast, all his money sunk into ultimately unsuccessful lawsuits against the hated Buck Duke who absconded with the name "Bull Durham" and made his empire upon it. So McElwee observes that he's on the wrong end of a lose-lose transaction: He didn't get any money, but he got the guilt from knowing a direct ancestor helped addict America to the sot weed.

And he notes -- and examines at length -- the irony by which all of old McElwee's descendants, except him, were the inheritors of a "pathological trust fund," in that they all became doctors who tended those dying of lung cancer. So if they didn't get rich, they at least got jobs out of the deal. And since Ross has been a camera addict since boyhood, he has film of his late father, the surgeon, at a younger age, one of those salt-of-the-earth types you'd trust your life to -- many did. But what McElwee seems to be most interested in in this film is a quality of memory, that strange place where fragments of images and family urban legends and the Official Record all mesh; we have a convincing portrait of a man simply trying to understand who he is and where he came from and whether Gary Cooper actually played an ancestor.

In his quest, he advances on many different fronts, illuminating each with a bright flash of character, a subtle visual joke, an arresting image. The funniest sight in the film is when he discovers that in his home town there's an actual McElwee Park named after the old capitalist, which consists of two benches on a scruffy patch of ground overlooking a parking lot of a trucking firm. He visits it and films himself sitting on what appears to be the most uninteresting piece of land in the South, as if he's waiting for an epiphany to arrive, which of course it never does.

Then there's a sequence where he interviews the 77-year-old Patricia Neal, who had been young and in love with Gary Cooper when she starred with him in "Bright Leaf," and McElwee hopes desperately that she'll have some illuminating memory. Instead, the old legend is tough and self-absorbed, and her answers to his deeply neurotic questions are stock. She isn't letting him -- or anyone -- in, thank you very much. (Anyone who's ever interviewed a truculent celebrity will chuckle at the exquisite awfulness of this encounter.)

On and on the movie goes, in some sense futile from the beginning because it seeks that which cannot be found. But it finds other things: One is the power of Gary Cooper as a movie star, because even in the mediocre snippets of the mediocre film McElwee shows, the big guy's charisma blasts out, bleaching the frame of all information except for his presence and state of mind.

Another little filigree seems to illustrate the pointlessness of intellectuality in subtler issues of the heart: He interviews a Czechoslovakian film theorist who actually takes over directing the movie by placing McElwee in a wheelchair that he pushes around backward while McElwee films him from the seated position ("It has to be kinesthetic!" the man barks), and the guy can say nothing about Curtiz the filmmaker and can't begin to understand the psychology of McElwee's connection with "Bright Leaf."

At the end, a small, essentially meaningless mystery has been solved. But McElwee is still the poor artistic son of a North Carolina medical clan, and he hasn't resolved any of his ambivalences about his great-grandfather's failed tobacco entrepreneurship. Nothing's changed, except the audience has had a brilliantly amusing couple of hours.

Bright Leaves (107 minutes, at Landmark E Street) is not rated and contains nothing objectionable.

A North Carolina tobacco farmer in "Bright Leaves," the latest from filmmaker Ross McElwee.