MOVIES ABOUT country boys who come to the city to make it big used to be made about tycoons and entrepreneurs. The rise of rock as the most dynamic mass art form has passed the heroic mantle from businessmen and badmen to rock stars. And rock has accentuated a theme which has always been implicit in the hero as desperado: a morbid fascination with living life as quickly as possible, with life only in the present, and pain collapsed into conclusive drama.

The Hendrix and Joplin legends satisfy precisely this fascination, and a whole school of films has capitalized upon this by exploiting rock's ability to suspend and heighten experience. Monterey Pop, Woodstock and Gimme Shelter use the camera to merely broadcast and reproduce the excitement generated by the music and the performers themselves. Rock and film sometimes mesh as neatly as bass and lead guitar. Gimme Shelter is at its best when the colored lights play over Jagger's body, and the Stones possess the stage. Offstage, without the protection of its excellent music, it grows tiresome.

The Harder they Come is in some sense a landmark film. Its camera movement and its heavy use of rock are inherited from films like Gimme Shelter. Its attempt to abstract from its music, and the variety of sounds it is able to utilize, mark it as an important work. What makes it excellent, and almost great, is its ability to channel the volatility and emotion of the music, without allowing sound to overshadow the purpose of the film.

The sound is virtually continuous; it ranges from rock to revivalist hymns to the background whine of transistor radios to the economical singsong (and sometimes subtitled) Jamaican English of its principal characters. And the sound is uniformly good. Jimmy Cliff's rock is strong and vibrant. The title song is a top 40 hit whose tune may stay with you for a few days, and the church music is professional, loud and compelling. All of it buoys up the film with movement and vigor.

IN A SERIES of powerful shots of downtown Kingston, music enables Director Perry Henzell to move quickly from closeup to closeup without disrupting the viewer's overall perspective. Music knifes through the film as the constant reminder of the attraction of the successful hustle. Henzell is able to spotlight key segments of dialogue by removing the mantle of sound, and isolating them in sudden stark silence.

The Harder they Come is a Jamaican film. Henzell, a rich white native of the island (producer, director and author) has made a film that sparkles with an understated, bitter native irony. For example, after waiting hours for the monopolist who controls the island's record business to emerge from the gates of his mansion, a group of six bedraggled hopefuls gathers around the hood of his gleaming white Mercedes and performs a carefully orchestrated song. The boss leans back for a moment, his sunglasses sharp stars in the sun, and suddenly interrupts them. "Too slow. I can't use it." The audience laughs at the irony of the fact that the boss so misjudges these accomplished itinerants, the black Beachboys rejected by El Exiente.

Jimmy Cliff, a Jamaican rock singer, plays Ivan, the country boy who comes to the city determined to become a top singer of "reggae" [what polite Jamaicans used to call ragamuffin music; it is a sort of synthesis of American rock and Jamaican native sounds]. Cliff found his way to shantytown from a little village in the country. He came to Kingston to go to technical school, quit after a very short while, and then hustled himself into the music business. For him, The Harder they Come is really part of the hustle.

IVAN ARRIVES in Kingston and is immediately ripped off when he finds that in the big city even getting directions cost money. "You think town is easy," cautions a relative Ivan finds in town. "I can sing," he replies, the young Elvis Presley waiting for his inevitable break. Ivan gets the name of a churchman who is to give him a job, and begins his move through a series of rackets.

Style is all in this world. The revival meetings in the preacher's church and the rock and reggae that float over Kingston like a frowning cloud, are both variations on the same theme. To prosper is to create reality--to find your medium and sell it. In Jamaica, the sudden graft of Western society on to a pre-industrial culture has produced a society where the only alternative to living a mythical electronic life is the clutching poverty of the shacks of West Kingston.

Ivan marks time, working for "Preacher," as the religious boss is called by employees. He cuts a record for the island's one and only producer, and is forced to accept $20 for the rights. The Jamaican record industry is dominated by two or three large producers, who force poor performers lacking capital to accept whatever the producers will pay--usually around $20 a tune. The producers control what the radio stations play, and at the same time try to make sure that no one artist becomes wealthy or well known enough to challenge their position. When Ivan attempts to push his own record, working through a DJ he knows, he is quickly rebuffed. Friendship cannot beat the hustle.

Forced out of the preacher's household because of his romance with the churchman's ward, Ivan turns to running dope for a living. When he attempts to rebel against the strictures of the ganga trade--which lives under the protection of a corrupt government--the penalties grow heavy. Dope brings in high profits for certain middlemen; low wages are paid to the growers, and to the runners as well, who move the stuff between the countryside and the cities.

IT IS WHEN the police hassle Ivan for refusing to accept the tiny share of the ganga profits which the authorities have delegated to the runners, that the calm confidence, the disguised naivite which Ivan has imported with him from the country to Kingston breaks down. When he refuses to submit to capture, killing a pursuing motorcycle cop, he finds his role as the renegade. Having been through the religion and music rackets, Ivan finally rests content with the rule of the gun. It marks his outright acceptance of the violence which lives behind the rackets.

Brandishing his weapon, he shoots his way out of a police trap. Then, playing the pimp, he steals a white convertible and circles the car on a golf course. The tail lights flash on the green, and Cliff's song "You can make it if you really want (but you must try)" blares accompaniment. With childlike delight, he pursues the boss of the ganga runners through the streets of Kingston, shooting at his heels.

Ivan becomes a media hero. Jamaica's population, nearly two-thirds illiterate, communicates by radio. Make it on the radio there and you are whatever you say you are. The fickleness of the instantaneous media courses through the film. Having learned his new role from the movies, Ivan poses for pictures with six guns circling his fingers, and sends them to the newspapers. He writes his logo on walls like graffitti on the IRT. And as the news of his exploits spreads, his suddenly rediscovered $20 record rises to the top of the charts.

It is at this point that the movie begins to weaken. As Ivan rises to brief status as renegade folk-hero, the film loses its credibility. Ivan is more a rip off artist than a Robin Hood, an improbable hero.

THROUGH IT ALL, Jimmy Cliff seems too intent on playing himself, perhaps too aware that he has gone through all of this once before. He is a touch too calm, too effortlessly acclimated to the city for the role of the naive country boy he must assume early in the film.

Henzell's characters never develop fully. They seem caught between fully dimensioned portrayal and the mythical world in which he attempts to place them. And they never attain either.

For a nation like ours, lately so concerned with the effects of the media and its distortions, Ivan is a frightening demi-god, the parody of our vicarious dreams. When he first comes to Kingston, Ivan goes with a friend to see a Western film. The hero steps in front of a band of enemies, clothed in red cape and handy Gatling gun, outnumbered 25-1. "They're going to kill him," Ivan screams. But his worldly-wise companion schools him. "Don't worry mon--the hero never dies until the last reel."