Half-baked and halfhearted though it is, "The Divine Garbo," a TNT documentary premiering at 8 tonight on the cable channel, does offer provocative glimpses into the life and art of one of the screen's most romantic figures, an actress who became an enigma to rival the Mona Lisa.

Unfortunately, "glimpses" is about it. The program is only 46 minutes long, and it rushes through the films of Greta Garbo -- who died in April after decades of seclusion -- pell-mell and even willy-nilly. A famous clip from "Ninotchka," for instance, is cut short before the payoff, when Garbo returns Melvyn Douglas's smooch with a passion.

TNT, one of the Ted Turner networks, is in a unique position for Garbography since Turner owns all of Garbo's American films. Unfortunately, forces-that-be chose to crank out a quickie rather than attempt a definitive and illuminating study. Cable flubs it again.

Narrator Glenn Close is seen on camera strolling around the stage of a Broadway theater where "Grand Hotel" is playing -- a tenuous link in that the musical is based on a film in which Garbo appeared. When it's time to discuss that picture, Garbo's performance is assailed as having been "forced" and "overacted."

What purpose did writer David Ansen, the Newsweek film critic, think observations like that would serve? Maybe that Garbo might be watching and would try to do better next time?

The rarest footage seen on the program is the earliest, shots of Garbo as a plump model in her native Sweden and in a succession of Swedish silents. Mauritz Stiller, her mysterious mentor, made her lose 20 pounds and wiped that smile off her face, and what the world would know as Garbo began to take shape.

One yearns to learn more about Stiller, who was homosexual, the script says, and who died in 1929 at the age of 45 back home in Sweden, Garbo's photograph clutched in his hand.

Garbo challenged sexual stereotypes on the screen, it is noted; she tended toward the "dominant position" in her love scenes. It is said she brought to films the "tantalizing spice of androgyny." A poster for MGM's "Two-Faced Woman" shouts, "Go Gay with Garbo!" But of course "gay" had a different meaning then.

The program is brightened by a couple of montages, including an opener of Garbo sightings accompanied by an unidentified crooner trilling "Just the Way You Look Tonight." He returns later to sing "They Can't Take That Away From Me" over a montage of Garbo in wild hats.

Close says of Garbo that "to guarantee her immortality, she remained a mystery," as if Garbo's early retirement and years of quiet isolation were some sort of publicity stunt. Surely it is preferable to think that her reasons for leaving the public eye were private and dark and had nothing to do with image.

In "Camille," the classic that follows "Divine Garbo" on TNT at 9 p.m., Garbo says, "Perhaps it's better if I live in your heart where the world can't see me." This documentary on Garbo and her myth only scratches the surface, but what a surface it was.