Why does the ''Star Wars'' saga appeal so deeply to so many people? A clue lies in the tag line of the series: ''A long time ago in a galaxy far, far away . . . .'' Exactly. The key ingredients of these movies don't look to the future, but to the past.
The plots revolve around struggles between good and evil, with conventions as ancient as legends, as timeless as folk tales. The characters are archetypes, earnestly rediscovering adventures and emotions that have engaged countless heroes and villains before them.
Children watch with wonder as basic human forces take on form and color, whizzing toward the comforting resolution that surely waits after the next cliffhanger. Older folks watch more skeptically, but it's a rare grown-up who doesn't feel some stirrings of childhood - that ''long time ago'' when we were ''far, far away'' from the adult awareness that things aren't really quite so simple.
As it happens, though, the ''Star Wars'' vision has gotten more complicated since its genesis six years ago. The first episode was a crisp conflict between good and bad guys, drenched with adventure and comic relief. The second installment, ''The Empire Strikes Back,'' slowed the pace and brought in ambiguities. At the final fade-out, it looked as if one good guy might be doomed forever; and the worst villain now claimed to be the hero's father, making us wonder how - if this was true - the story could be resolved without cheating or breaking some taboo.
Which brings us to Chapter 3, the long-awaited Return of the Jedi. Yes, fans, the action is as fast and frazzled as ever, breaking into cinematic hyperspace every chance it gets. New henchmen for the evil Empire pop up everywhere, as do new helpers for the heroic rebels. A whole gang of newly concocted aliens make their movie debuts, and there's even a rehash of the much-loved ''cantina'' scene, with a screenful of spaced-out creatures ranging from monstrous to cuddly. What more could a ''Star Wars'' admirer ask?
Yet the serious side of the saga has also grown deeper. Just about everyone seems to be an archetype now: Luke Skywalker is an idealized ''knight,'' Han and Leia make a perfect couple, Yoda and Ben Kenobi positively ooze the wisdom of the ages. The relations are more involved and tormented than ever, with Luke torn by new emotions toward Vader. And it's clear that the story's end is near, lending fresh momentum - even urgency, at times - to each new wrinkle and intrigue.
Does it all hang together? Yes, and very well, though not every scene meets the movie's generally high standard.
On the down side, much of the action seems perfunctory. Especially near the beginning, there's a sense of routine to the slam-bang effects, as if obligation rather than enthusiasm dictated them. Some sequences are too childish for comfort, too, as when Jabba the Hutt - a comical cross between Moby Dick and the ''Alice in Wonderland'' caterpillar - mixes conventional nastiness with behavior more grotesquely gross than anything earlier in the series.
By contrast, the climax is a model of classical moviemaking, as three parallel plots - a space battle, a land battle, and Luke's showdown with Darth - race to a climax at the same time. The special effects also come alive here, filling the screen with dazzling motion and color. A chase through trees on airborne racers provides the most kinetic scene in ages. And the new characters include a whole nation of fuzzy something-or-others that make up in cuteness for what they lack in individuality. Look out for another merchandising craze if ''ewoks'' take over the adorableness mantle from E.T.
In sum, ''Return of the Jedi'' is a sure-fire hit, reprising the dynamic ''Star Wars'' themes while blazing trails of its own. No movie will ever have the same bite and surprise as the original ''Star Wars.'' But the new chapter brings the first trilogy of the series to a rousing finish that's guaranteed to please all but the fussiest fans - and may provide the momentum to push the saga further, toward its ultimate goal of nine films.
Who gets the credit? First mention goes to George Lucas, who dreamed up the whole ''Star Wars'' notion, directed the first installment from his own screenplay, and served as executive producer and co-writer of ''Jedi.''
Next comes Richard Marquand, the Lucas collaborator who sat in the ''Jedi'' director's chair. Like director Irvin Kershner of ''The Empire Strikes Back,'' he undertook the ticklish job of realizing Lucas's vision while bringing his own skills and personality to bear on the finished product.
Filling out the list are the other cinematic wizards who contributed their special talents, from the stars to the technicians and special-effects personnel. Kudos for all. Lunch with 'Jedi' director
Of course, as large and skilled as the Lucas organization is, it's still subject to problems. The director of the last ''Star Wars'' chapter, for example , reportedly had trouble balancing his own ideas with Lucas's during the hectic ''Empire'' production period. So over lunch in New York the other day, I asked Marquand how things had fared with him. He said few obstacles had cropped up. Before shooting began, he made sure Lucas would be available for consultation, so difficulties or disagreements could be ironed out as they arose.
For the rest, he avoided thinking of himself as the lone ''author'' of the movie. Rather, he saw his job as conducting a symphony composed by Lucas - with the ''composer'' standing nearby to discuss matters of taste, tone, and interpretation.
Under this arrangement, Marquand feels he stayed true to Lucas's conceptions. Yet he played an active part in the movie's construction, and ''Jedi'' would surely be a different film if a different director had overseen it. Before filming commenced, it was Marquand who opted for lots of disguises in the opening scenes; suggested that the Empire's final defeat could be as much symbolic as physical; and brought Yoda back for a major role instead of merely a ''guest appearance.''
And most important, it was apparently Marquand who underlined the emotional and familial strains of the story.
''Most of the work I've done, and everything I care about, involve human relationships - love, hate, loyalty,'' he told me. ''That's what pulled me into the story, not a fixation on the distance between Venus and the moon in parsecs.''
Yet he enjoyed the special-effects aspect of ''Jedi,'' too. ''The filmmaker in me loves all that,'' he said. ''I actually got to do those things I've seen and loved on the screen for so long!''
In fact, Marquand feels there is little distance between feeling and physicality in cinema. ''The next step from emotion is usually action,'' he says , ''and often fairly violent action, even if it's just a violent embrace. Thus he felt no contradictions when it came to integrating the most expansive and most intimate elements of the ''Star Wars'' myth; they're really two sides of a single human condition, he believes.
Marquand says his aim in directing ''Jedi'' was to reach out to ''Star Wars'' fans of all ages. ''I realized that the kids who grew up on 'Star Wars' have - well, grown up!'' he explains. ''Yet there's a new generation coming along, too. I wanted to offer something for all of them - a dense, complex, highly charged piece of film, not just another sequel.''
Beginning next Wednesday - the sixth anniversary of the original ''Star Wars'' premiere - audiences can judge whether Marquand & Co. have juggled their ambitions and achievements as well as they hoped to. Whatever the verdict, Marquand is off to a very different territory for his next film: a love story set in Paris. ''No robots, no special effects, no speed of light,'' the director says with a happy sigh. ''Just more emotions, relationships, feelings, and those things that really matter. . . '' Jazz films get a boost
There's good news for jazz and movie fans. Bruce Ricker - maker of an excellent jazz documentary, ''The Last of the Blue Devils'' - has formed a new distribution company that will specialize in jazz and blues pictures. Aptly called Rhapsody Flims, it will serve all American markets including theatrical, nontheatrical, TV, and videocassette outlets.
The firm claims to be the first ''central company'' where exhibitors and buyers can turn for jazz movies. Among its offerings will be works by such established filmmakers as Les Blank and D.A. Pennebaker, featuring notables as diverse as Lightin' Hopkins and Sun Ra. Rhapsody will also be booking agent for David Chertok, an archivist billed as having the world's largest jazz-film collection.
In addition, Ricker and Rapsody plan to distribute films of other kinds, beginning with a documentary on Athol Fugard, the South African playwright. Since documentaries are among the trickiest of all movies to bring before wide audiences, one wishes the new enterprise well.