When I first saw "The Americans" in Rome, in 1961, I had a sort of vision. A friend, a young Italian, handed me that Grove Press book of photographs by Robert Frank, and Italy dissolved.

A streetcar in New Orleans, a segregated streetcar, 1956: Frank's perfect, unposed photograph, part poem and part grid, was not one picture only. I saw the faces of the passengers, the blacks behind the whites, and the strange, reflected mysteries hovering above them. Frank's pictures fell like hammer blows. I saw a brick wall in New Jersey, a highway in New Mexico, urinals in Memphis, Oral Roberts on TV. It might have been the glare xr on the whiteness of the tablecloth, or the strength of the espresso. I saw jukeboxes and cowboys and broken city streets. Sitting in the sunlight there, as if in revelation, I remembered an America I did not know I knew.

No other book of photographs, not even Walker Evans', and few works of art of any sort have ever hit me quite so hard. Frank's entirely untricky, often melancholy photographs were relatively new then. I've memorized them since. Twenty-five years later I can no longer say whether my gray memories of the last years of the '50s are wholly mine or xr partly his.

The big jukeboxes are gone now, so are segregated trolleys and hot dogs sold for 18 cents, but Frank's pictures of the '50s -- "souvenirs," he calls them, "strange objects from another age" -- do not yet feel antique. Other visions of America abroad at the time -- Norman Rockwell's, Lucy's, Ike's -- now feel like frothy fantasies. But Frank's vision feels like truth.

His technique wasn't special. He didn't seem to have one. Frank did not demand, as Ansel Adams did, flawless, focused prints, nor did he rely, as Evans often did, on the crispest compositions. Stick-in-the mud critics dismissed him as incompetent -- Frank's "prints," wrote Arthur Goldsmith when "The Americans" appeared, "are flawed by meaniingless blur, grain, muddy exposure, drunken horizons and general sloppiness." Photography's ideologues were also troubled by his pictures. Frank's sympathies were strong, but his politics weren't clear. When he photographed the Wild Ones in their leathers on their Harleys, starlets, transvestites, retirees in Florida or South Carolina blacks, he did so without lecturing. Frank was no crusader, no Lewis Hine or Russell Lee or Dorothea Lange, he had no ax to grind.

Some used to say his mastery was tied to his reporting, that Frank, who'd come from Switzerland in 1947, had learned to see Americans -- as had Dickens and De Tocqueville -- more clearly than Americans could ever see themselves.

That old, too-easy view of Frank the straight observer is overturned xl completely by "Robert Frank: New York to Nova Scotia," his unforgettable retrospective -- it will not come to Washington -- now on view in Houston at the Museum of Fine Arts.

Frank's vision is religious, his gift a gift for witnessing. All his pictures feel like prayers, or if not like prayers, laments.

The Houston exhibition, organized by the museum's Anne W. Tucker, includes photographs from the '40s, and new ones from the '80s, and when all 188 are come upon in sequence, the time-bound facts that they depict come to matter less and less. It's not his subjects one remembers, it's his searching for transcendence.

Once, after seeing an exhibit of Bill Brandt's photography, Frank tried to say what hit him: "Well it got to me: right through my eyes into my heart and to my stomach. I heard a sound and, and a feeling inside me woke up. Reality became mystery." Frank's retrospective, too, is dense with revelations. His early works are filled with love. His late ones suggest martyrdoms. Every picture here, no matter what its subject -- an empty blacktop road, Frank's children or his wives, Mick Jagger, Robert Kennedy, or a garbage dump half-hidden by Nova Scotia snow -- seems a portrait of his soul.

Frank was born in Zurich in 1924, and lived there through the Hitler time. His art, from the beginning, has sought out sacred signs. "The Americans," for instance, is a volume filled with icons, with crosses of all kinds, and gas pumps that seem monuments, and with flags that somehow feel like veils and like shrouds.

Jack Kerouac was right. He wrote, "After seeing these pictures you end up finally not knowing whether a jukebox is sadder than a coffin. That's because he's always taking pictures of jukeboxes and coffins -- and intermediary mysteries."

Kerouac and Frank were pals; they drove to Florida together in 1958. Kerouac wrote the introduction to "The Americans," and then narrated "Pull My Daisy," a movie Frank directed in 1959. That funny, gritty film was based on an actual encounter (at Neal Cassaday's house in California) between a bunch of poets and a visting Swiss bishop who brought along his mother. Richard Bellamy played the bishop, Alice Neel played his mother and Gregory Corso played Jack Kerouac. Peter Orlovsky and Allen Ginsberg appeared as themselves.

Bellamy, while wandering through Frank's show, was asked the other day if he'd sensed the power of Frank's pictures in the long-gone 1950s. "Not the power, really," Bellamy replied. "Not the power -- but the gristle."

It's the truest movie ever made on the beat generation -- beat as in "to beat," and beat as in "beatitude." If the beats had formed a church, Frank would be among their saints.

If you've ever slept, as he did, in sheetless New York crash pads, or submerged yourself completely in Hank Williams and John Coltrane, or plunged into the wild grimness of the urban underground, and broken all the rules, you will understand the spirit of Frank's '50s art.

"Robert comes out of this totally formal situation: middle-class, Jewish, Swiss," his friend Rudy Wurlitzer has said. "Where he saved himself was to embrace the opposite." Frank has told Anne Tucker that he came here as an "innocent ready to unlearn what the Swiss had taught him." He was tired of respectability, and prosperity, and fear.

"I think what I learned as I was growing up was all negative," he's written. "I didn't want to be a businesman, to make more money, to buy a better house, a fur coat. Our relatives were all concerned with the same thing. There was a silent struggle, who will come out on top, make the most money . . . I saw fear in my parents. If Hitler invaded Switzerland, and there was very little to stop him, that would have been the end for them . . . It was on the radio every day. You could hear Hitler cursing the Jews, it's forever in your mind. Because I lived with that fear it made me less afraid."

New York, for the young Swiss, was a New World without rules. Within months of his arrival he was shooting in the streets with the photographer Louis Faurer. Though both men had been hired by Alexey Brodovitch at Harper's Bazaar, the chic was not Frank's field. "I did illustration work for magazines: bad women, good men, old people, lonely people. That was my thing," he's said.

In 1949, when Frank sailed to Italy, his girlfriend Mary Lockspeiser tried to stowaway on board. She was then 16. He photographed her often. Her pure and timeless beauty takes the viewer's breath away. They were married the next year.

In 1954, Frank applied for the Guggenheim Fellowship that led to "The Americans." Brodovitch of Harper's, Alexander Lieberman of Vogue, Walker Evans the photographer, Meyer Schapiro the art historian and Edward Steichen, curator of photography at the Museum of Modern Art, wrote his recommendations. He was awarded $3,000.

Frank's impulse to get going was as peculiarly American as Ishmael's to go to sea, as Huck's to go down river, as Kerouac's to go on the road.

"We just took off in a car," Mary Frank remembers. "I thought we were going off on some sort of picnic. Two kids, one of them sick, no place to wash the diapers. I couldn't drive. We didn't know where we were going to, where we'd stay."

Their journey, quite appropriately, was a series of adventures -- Yale commencement in New Haven, Conn., the half-mad preacher on the riverside in Baton Rouge, La., the corpse beside the road in Flagstaff, Ariz. Frank was busted twice. The first time was in Detroit ("My night in jail," he told Mary, "was not as funny as it sounded"). In November 1955, he was arrested once again, this time in Dermott, Ark.

"I noticed that he was shabbily dressed, needed a shave and a haircut, also a bath," the arresting officer, Lt. R.E. Brown of the Arkansas State Police, explained in his report. "Subject talked with a foreign accent . . This officer investigated the subject due to the man's appearance, the fact that he was a foreigner and had in his possession cameras and was possibly in the employ of some unfriendly foreign power and the possibility of Communist affiliations."

Frank journeyed as a seer, an explorer, a chance witness. He photographed the poor, the rich, the 1956 Democratic convention in Chicago, factories and drive-ins, funerals and bars. No story line inspired him. He depended on his instincts, his reflexes and sympathies. Responding to his own heart, he peered into ours.

"The truth is somewhere between the documentary and the fictional," he said, "and that is what I try to show."

"To Robert Frank I now give this message," wrote Kerouac. "You got eyes."

Frank has never cared for money. Slick work drives him wild. He could not bear, for instance, the art of Helen Frankenthaler.

Her "paintings look at me and I look at them," he wrote in 1969. "A cold fury comes over me, what white emptiness, what meaningless elegance, what indulgence into TASTE and intellectual snobbery. What makes a show like Frankenthaler's possible is Power and Money . . That's the way it is in America . . true but sad . . "

One of the recent pictures in his Houston retrospective is a large collage of portraits of his artist neighbors in Manhattan in the '50s -- Claes Oldenburg, Franz Kline, Bob Thompson, young Red Grooms. The picture, like so many of the artist's recent works, bears a scrawled inscription:

"Remember. Inspiration and influence. 1950 New York painters . . . More spirit less taste. Remember. Keep going . . . "

Frank is still the least guarded of the 20th-century masters. His pictures are not chilled, as are Cartier Bresson's, by European ironies; nor are they protected, as Evans' often are, by emotional reserve and aristocratic distance. In a world more fair than ours a witness so inspiring, an artist so in touch with his inviolable emotions, would be granted all the great rewards, happiness and peace and luck.

Robert Frank deserves the best. He didn't get it. A sadness inconsolable hovers over the newer objects in his show.

His son Pablo spent years in hospitals, and one sees that in his face. His beloved daughter Andrea was killed in a plane crash in Guatemala in 1974.

One deeply moving picture of the emptiness surrounding Frank's Nova Scotia home was taken in her memory: "For my daughter Andrea who died in an airplane crash at Tical in Guatemala on December 23," the legend reads. "She was 21 years, and she lived in this house, and I think of Andrea every day."

In 1958, Frank gave up still photography if only for a while. In many of his newer works one feels his disappointment, isolation, loss.

In 1972, when the Rolling Stones commissioned Frank to film their U.S. tour, he shot not just their concerts, but their groupies and their drugs, and made a movie so explicit the band blocked its release.

He's been as open with his own life. One of the newer pictures here is an image of pure loss, a photograph of mirrors that reflect almost nothing except a ghostly hand holding up a devil toy. Frank has written on the image: "Sick of goodbys."

Last winter he sent a letter to curator Anne Tucker: "I am making souvenirs," he wrote. "I am making memory because that is what I know, that is what I learned to know about, that is hopefully an expression of my true feeling. To tell my story. How I know the weakness of these concepts . . . It is Summer in the Heart of Winter."

Thirty years ago Frank photographed the rest of us. Nowadays his only subject is himself.

Some 15 years ago, atypically, Frank signed away the prints he'd made to date, and his rights to produce more -- "for ten years middle range income," writes Allen Ginsberg -- to a pair of New York businessmen. Dealer Harry Lunn contracted for many and sold them, for small prices, to lots of us in Washington. Frank, as one might well have guessed, later soured on the deal. It was at his insistence that the businessmen he dealt with have had their names excluded from the fine catalogue accompanying Anne Tucker's Houston show.

Frank's touring retrospective, had it come to Washington, might have been the capstone of the series of exhibits of New York School photography mounted by the Corcoran. But the Corcoran refused the show. So, inexcusably, did all museums in New York. Easterners who wish to see it will have to go to Cleveland. It will be on view in Houston through April 27, and at the Cleveland Museum of Fine Arts from July 22 through Aug. 31. Thereafter it will travel to the Minneapolis Institute of Art, the Los Angeles County Museum of Art, and the University Art Museum, Berkeley, Calif.