''The Source,'' a stirring, kaleidescopic documentary about the Beat generation and its legacy, spans from the exultant 1940's photo of the young friends Jack Kerouac, Allen Ginsberg and William Burroughs to the ''Jeopardy'' show on which contestants could win money by asking, ''Who were the Beats?'' (''Allen Ginsberg, Jack Kerouac and Lawrence Ferlinghetti were part of this group of writers.'') And it moves beyond, to the point of becoming a ghost story. ''It's eternity all the time, so there's no point being nostalgic for eternity,'' Ginsberg (who died in 1997) is heard saying. But that wisdom runs counter to the moving experience of watching this film unfold.
The wizardry of Chuck Workman is well known to viewers of the Academy Awards broadcast, which has been dependably brightened by his witty, rapid-fire compilations of film clips. And his acumen remains just as sharp in this feature-length format. Mr. Workman, who also made a feature about Warhol, indeed packs in so many different facets of his subject matter that he would seem to risk glibness; this is, after all, a film in which Bob Hope, Alfred Hitchcock and Fred Flintstone can each be found going the goatee-and-beret route for parody's sake. But ''The Source'' has been made much too knowingly and affectionately to wear thin.
Instead, Mr. Workman's comprehensiveness is an obvious virtue. However well known the assorted Beat legends have become, there is a cumulative power to seeing so many of them evoked so colorfully in a single film. And even viewers who know a great deal about Kerouac, for example, may be surprised by his later talk-show appearances, like the one in which he blearily insisted that the Vietnam War was a Vietnamese plot to garner American Jeeps. Or the one in which he is blindsided by William F. Buckley Jr., who is able to pronounce ''yippies'' as if it were a dirty word.
The film needn't delve explicitly into the none too hip side of Kerouac revealed in his later years. The pictures seen here do a lot of the storytelling by themselves, especially when images of these rebels at their most young and beautiful are contrasted with scenes of their later years. Dazzling scenes of Neal Cassady dancing bare-chested, with the look of home-movie snippets and an air of utter joy and abandon, speak volumes about why Cassady became legendary even among his own friends. ''He wasn't destined to grow old,'' Mr. Ferlinghetti says of him. ''He was always young and he always will be.''
In addition to offering a magic-bus trip down memory lane, ''The Source'' has serious work to do: capturing the spirit of Beat poetry, watching it evolve from passionate outpourings into a source of caricature and following it through into later cultural manifestations. In tune with the early years, several well-chosen actors bring the writing to life: Johnny Depp intoning Kerouac, John Turturro giving a fiercely emotional reading from Ginsberg's ''Howl'' and Dennis Hopper with the right hat and the right attitude for echoing Burroughs. Perhaps the purest expression of the Beat ethos comes slightly later, from Ken Kesey, who is asked by an incredible interviewer: ''Mr. Kesey, do you feel that you have the right to do what you want, whatever you want and still live in this world?''
Mr. Kesey answers: ''I feel that a man has a right to be as big as he feels it in him to be.''
''The Source,'' which opens today for a two-week run at the Film Forum and makes for indispensable viewing, later makes connections with hippies, the 60's anti-war movement and a 70's culture with an obvious debt to Beat life-style experimentation.
And finally, there is the official recognition: official commemorative ceremonies, Gap ads featuring Beats in khakis and even Kerouac's words emblazoned on a coffee mug. The film could excoriate these manifestations but instead finds them amusing. It has no doubt that the Beats still have true descendants, and that they keep the faith.
-Janet Maslin, The New York Times, 1999