IF GEORGE LUCAS carries through on his grandiose plans, the saga of Star Wars could drag on longer than the Thirty Years War. But if the rest of the installments in the series are as good as the two released to date, Lucas can prolong his battles in space as long as he wants--or as long as movie-goers continue to flock to the films in record numbers.

At this point Lucas--director of the original 1977 Star Wars and executive producer of this summer's The Empire Strikes Back--plans to depict the Rebellion's struggle against the diabolical Empire in nine films, divided into three trilogies. The first two segments, which relate the story of would-be Jedi knight Luke Skywalker (Mark Hamill), are actually episodes IV and V of the envisioned series.

But there's no reason to know how everything fits into Lucas's cosmic scheme when you see The Empire Strikes Back. What's important to remember is that when we last saw Luke, Princess Leia (Carrie Fisher), Han Solo (Harrison Ford), Chewbacca (Peter Mayhew), C-3PO (Anthony Daniels) and R2-D2 (Kenny Baker), they were celebrating their destruction of the Empire's ominous Death Star, oblivious to the escape of arch-nogoodnik Darth Vader (David Prowse).

In the three years since that victory party, the Rebel forces have somehow wound up hiding from a revitalized Empire on the planet Hoth, which is nothing more than an oversized ice cube. Darth Vader and the Empire quickly discover the Rebellion's snow hideout and descend upon the planet with a force of huge, camel-like tanks.

Most of the Rebels easily evade the Imperial invasion, but Han, Leia, Chewbaca and C-3PO stay behind until Darth Vader's black robes nearly envelop them. They then take to the dilapidated and constantly malfunctioning Millenium Falcon, in which they escape from their crumbling arctic fortress only to be pursued relentlessly by a fleet of Imperial star cruisers.

Meantime, Luke and R2-D2 take off from Hoth in search of Yoda, an 800-year-old, three-foot-high Jedi master and wise-cracking philosopher who teaches Luke the intricacies of The Force. Yoda--a muppet-like creation operated by Frank Oz (Miss Piggy's human half)--proves a special effects miracle in a film where every frame contains an intricate cinematographic maneuver. The puppet's retinue of facial expressions is endless; his ears alone are more expressive than any of his human co-stars, whose abilities to convey emotions seem to have suffered permanent frostbite on the frozen ice planet.

What matters in the Star Wars films, however, is not acting talent, but special effects and plot. The visuals in Empire are stellar (terrestrial scenes--especially those on Yoda's planet, Degobah--are spectacular as well), and the stereophonic sound effects roar with such stunning realism they make you believe that if noise existed in space, this is what it'd sound like.

The story line continues the basic good-guys vs. bad-guys theme of the original film. Darth Vader wants Luke, and he uses Leia, Han, Chewbaca and C-3PO as bait to lure the young hero into his chillingly evil clutches. Like its predecessor, Empire provides some genuinely comic moments and some downright dimwitted dialogue. But unlike the original, the new film contains some truly shocking plot twists.

The film also ends with no hint of resolution. Lucas and director Irvin Kershner take us to the edges of our seats and leave us there. If the quality of future Star Wars films remains as high as in the first two (or middle two, depending on your point of view), we'll still be there for episode VI three years hence--and for the last installment a generation from now.

Mary Poppins Directed by Robert Stevenson At the Pi-Alley

LAUGH, if you will, that another writer has decided American popular culture is in retrograde. Giggle, if you must, at the thought of a 19-year-old yearning for the good old days. And then go fly a kite. Or soar up a chimney, or jump through a chalk painting on the pavement into a land of animation.

Mary Poppins, made in the early '60s, provides a good index for figuring changes, cinematic and societal.

Hollywood, back then, worried less about "realism," perhaps realizing that to the unjaded, fantasy is just as "real" as car chases and gunship battles. As the opening credits roll, Mary Poppins sits on a cloud overlooking smoky London. Minutes later, a huge gust of wind blows away a host of prospective nannies applying for the position our heroine seeks. No one believes that it really blows hard enough to whisk away thirty mammarian matrons, or even that young women perch on English cloudbanks. But everyone believes in Mary Poppins, fantastic as she may seem, in a way which makes Luke Skywalker's authenticity pale.

Where have all the nannies gone? Julie Andrews glows with the aura of good, giving gentle Londoners a lesson in anti-imperialism. And Dick Van Dyke chimney-sweeps his way into the hearts and minds of even the most phlegmatic. By contrast, Jane and Michael's banker father sings, "Tradition, discipline and rules must be the tools." Mary manages to convert him eventually, though. The Politburo would surely censor this film--never has the case for healthy dissent been so eloquently stated. The message is simple: if you start worrying about conquering nations, you easily forget to feed the birds. And that can be very, very costly.

Some of us have sat through Mary Poppins more times than we care to remember, but the stunning animation never loses its novelty. The refreshing impish innocence of child actors Katie Dotrice and Matthew Garber reinvigorates the cynical and skeptical. Richard and Robert Sherman's score cuts across musical tastes and leaves the audience humming.