SAM FULLER is a bald-headed prostitute beating her drunken pimp with a shoe, a psychotic killer gunned down under an enormous "GIVE BLOOD NOW" poster, a black man in a Ku Klux Klan robe leading a race riot in a mental hospital, a weary World War II general shaking his head and saying, "Sneaking 3,000 men through this jungle is gonna drive me nuts!"

"The film is like a battleground," says Sam Fuller. "Love, hate, action, violence, death in a word, emotion."

Intense and iconoclastic, compared to everyone from Sen. Joe McCarthy to Thomas Hobbes and the Marquis de Sade, Sam Fuller is one of the most intriguing of all American film directors, a maker of self-described "cheap program fillers" who has ended up being idolized by intellectual critics as well as directors like Jean-Luc Godard.

"Fuller is an authentic American primitive whose works have to be seen to be understood," writes Andrew Sarris. "Seen, not heard or synopsized." Starting this Tuesday at the American Film Institute, a long-overdue 13-film Fuller retrospective will give those who dare the opportunity to do exactly that.

For Fuller's films are definitely not for the fussy, lace doily viewer. Sometimes sentimental, even mawkish, always crude and garish, they were often as not made very quickly and for very little money. Fuller's "Steel Helmet," for instance, was scripted in a week and shot in 10 days at a cost of $110,000, with Los Angeles' Griffith Park substituting nicely for the dusty plains of South Korea.

Yet what they lack in elegant production values these films more than make up for in enormous, purely cinematic energy. Because Fuller is nothing if not a writer/director with an intuitive understanding of the dynamics of film, of what makes for excitement on the screen. Everything is immediate, close to the surface, NOW.

Fuller's tight little movies may be simplistic, but they galvanize interest by fairly bristling with activity and zest. This is cinema reduced to essentials, potboilers raised almost to the level of art. even critic Manny Farber, who calls Fuller's mind "an unthinking morass at best," is in awe of this "all movie" technique. Says Fuller himself, "I love confusion, I love conflict, I love argument," all of which end up on the screen, often all at once.

Fuller comes by his freneticism honestly, through an apprenticeship in journalism before it got even part-way respectable. He entered the business as a 12-year-old copy boy on the New York Journal, became personal assistant to Arthut Brisbane, one of the great reporters of his day, and in 1928, at the ripe age of 17, joined the San Diego Sun as one of the youngest crime reporters in the country, soon to become the man, or so he says, who discovered the body of actress Jeanne Eagles and revealed her drug addiction to the world.

Fuller's experiences in this criminal netherland helped shaped the point of view that comes through in his films, the view of life as a treacherous, untrustworthy affair where the heros are cynics, criminals or both, inhabiting a violent, bleak world in which, as one of his characters puts it, "somebody has to get a bloody nose."

The director's other key experience was seeing action in World War II, winning the Bronze and Silver stars and a Purple Heart and observing the situations that led to such gutsy hyperthyroid war movies as "Merrill's Marauders," "Fixed Bayonets" and "Steel Helmet", where crusty Sgt. Zack, played by Fuller veteran Gene Evans, puts a hole in a North Korean "big enough to drive a truck through" and then screams, "If you die, I'll kill you."

"War is organized lunacy," Fuller has often said in interviews, adding that being at the front is "like having a huge fist twisting your intestines. It is sheer panic, a fear that never leaves you." Feelings like this have led to what he calls his "Six Commandments of the War Film," the first two being: "Don't stop the fight when someone is hit. If a guy is killed, carry on. What else can you do? and "Never allow a dying G.I. to bring out his wallet to look at his fiance's photograph. That never happens."

Much of Fuller's stronger, stranger work is set in the civilian era. "The Naked Kiss," for instance, featuring Constance Towers as the bald-headed prostitute, mixes treacly treatment of crippled children with some very nasty thoughts about small-town American society. And "Shock Corridor" has a scoop-crazed reporter committing himself to an asylum, where, among other indignities, he is almost clawed to pieces by a pretty fierce bunch of nymphomaniacs. Variety: "This film is so grotesque, so grueling, so shallow and so shoddily sensational that Fuller's message is devastated."

Perhaps the best single introduction to Fuller is "Pickup on South Street," his only film to ever win any kind of award, a Bronze Lion at the 1953 Venice Film Festival. Starring Richard Widmark as an amoral pickpocket who finds himself mixed up with communism and counterspys, it has a fine, gritty texture, an attractive performance by Jean Peters as the prostitute he comes to love and a classic one by Thelma Ritter as the tie-selling, information-squirreling Moe. According to Fuller, "Thelma missed the Oscar by one vote that year."

The time since "The Naked Kiss" was released in 1965 has been a strange one for Fuller. He has been involved in various projects that didn't work out and in films he disowned upon their release ("Shark/Caine" and "Dead Pigeon on Beethoven Street"), but he has also become more and more revered as a cinematic cult figure, with three different generations of directors - Godard in "Pierrot Le Fou," Dennis Hopper in the execrable "The Last Movie" and Wim Wenders in "The American Friend" - putting him in their films as a gesture of tribute.

Still, it is as a writer/director, not as what Li'l Abner used to call "an ideel," that Fuller functions best, so it is most pleasing to report that Fuller is currently shooting the feature film he has been planning for decades, a World War II drama called "The Big Red One," starring Lee Marvin and dealing with the hard times of the First U.S. Infantry Divsion, the director's almamater.

"I've seen wonderful pictures recently," Fuller said in an interview earlier this year, "comedies and dramas with nice boys and nice girls and their problems. That's fine, but I can't get into that kind of picture. I tried, but I want something that's exciting. It's not exciting to me if the man says to the girl, 'Look, I'll meet you a the corner drugstore at 5 o'clock.' I wouldn't write that . . . not unless I knew . . . when the girl walks into the corner drugstore, she's going to have her head blown off."

Here's looking at you, Sam.