Long before Calvin Klein became a marketing buzzword, there was Peter Max. He was the artist who elevated posters to art, who put his brightly colored cosmic designs on everything from sneakers to cookbooks to clocks. With his cosmic jumpers, stars, sages and seekers, he created a style that captivated an entire generation. Max was synonymous with the '60s. As he says, "Peter Max was a new consciousness."

By 1971 Peter Max was also big business. With his work displayed on more than $1.5 billion worth of retail merchandise, Max wasn't just a hippie artist. He was a corporation, which was more than he bargained for. How did Max handle it? "It's hard to explain," he says, "but I simply quit."

After 15 years of semireclusive retreat, Max, now 48, is showing himself to be no less hip than he was in the '60s. Last month the Circle Gallery in Los Angeles sold $500,000 worth of Max's art in two days. With new designs coming out on stationery, watches and tapestries, Max is exercising his marketing muscle anew. He's even talking about making his mark on Steuben glass and Tiffany china. "I want to do it all, but not on such a mass commercial level as I did then," he says. "I want to keep it nice, scarce and artsy."

The Peter Max most people remember, the artist with the Midas touch who won corporate favor by turning ordinary items into flower-powered trinkets, happened quite by accident. In 1966 Max printed a poster for a friend featuring a kaleidoscope of psychedelic characters; 18 months later nearly 3 million of his posters had been sold. "I got involved in applying my work on what I used to call 'stuff,' " he says. "It wasn't for commercial reasons. I just saw stuff and I thought that it needed things."

Before long, however, Max found he was too successful for his own good. "My life revolved around corporations, itineraries and nonartistic responsibilities," he says. "I just wasn't painting anymore." Indeed Max lived more like a rock star than a painter. He tooled around New York in a decal-covered Rolls-Royce, partied with the Beatles and claimed a yearly income of nearly $2 million. "I was a culture hero," Max says. "Life was crazy."

As the Age of Aquarius advanced, Max felt the need to regroup. The art was still selling, but the artistry had begun to wane. So Max settled down to work in his 18-room Manhattan duplex. "I decided I was going to do nothing but paint," he says. That meant saying no to the lucrative offers that streamed into his studio, like the one from the Texas oilman who asked Max to paint the bottom of his swimming pool, and the one from the soft drink company that wanted him to create posters.

Though less a mystery than the whereabouts of D.B. Cooper, Max's retreat was still enough to inspire rumors. Peter heard that he was a casualty of one too many psychedelic drug trips. He was also purported to be involved in an extended spiritual quest in Tibet. But the best story, which Max swears is true, had him landing his Jet Ski on the beach in Barbados next to a suntanned beauty, who looked up and exclaimed, "Peter Max! So that's where you've been."

Any decent sleuth could have found Max dabbling on the periphery of the art world. In 1974 he accepted a commission to paint a 10-cent stamp, and two years later completed the mural that greets immigrants at 235 Mexican and Canadian border stations. Says Max, "I thought, 'Wouldn't it be nice if there was a cheerful picture that would say, 'Welcome to this incredible country'?" In 1976 Max did the first of his Statue of Liberty paintings, now a July 4 tradition. This year he dashed off 11 portraits of Lady Liberty as part of the centennial ceremonies.

"America's most patriotic artist," as Max was dubbed by the Washington Post, was born in Berlin and raised in Shanghai. The only child of an import-exporter and a housewife, Peter claims he first displayed artistic aptitude when he experimented with crayons on his mother's steamer trunks at age 2. "She didn't spank me, she just made a big fuss," Max reports. "That was the greatest encouragement. I thought it was all about my work." After Mao Tse-tung rose to power, Max's family moved to South Africa, Israel, Paris and finally New York. Filled with "the colors of the world" at 16, Max began five years of study at the Art Students League, where he was schooled in realism, a genre he discarded after graduation because he lacked patience. "A nice realistic piece can take as long as a week or two," he explains. "I wanted to do a piece in five or six hours."

Except for the bright colors, Max's current work shows a departure from the past. Gone are the psychedelic landscapes and mystical islands, replaced by more impressionistic, adult images. Critics compare the new Maxes, with their vivid colors and free-form figures, to the Fauvist movement. "The times change," Max says. "You grow up." Similarly, the artist's personal credits are standard post-flower child—a divorce in 1976 after 10 years of marriage and two children with names that could only come from the '60s: son Adam Cosmo, 22, and daughter Libra Astro, 19. Max recently ended a relationship with model-singer Rosie Vela, 31, whose portrait graces several canvases in his studio. "She was the most beautiful woman I've seen," says a blue Max.

Anything but the tortured artist, Max goes to the easel first thing every morning, turning out paintings with the speed of a short-order cook. "Even before my shower I do something, anything, just to know that I've already painted," he says. "There's nothing else in life that attracts me as much. It's like being in love." Exhibitions in 140 museums worldwide (the Museum of Modern Art has six Maxes in its permanent collection) have caused paintings that sold for less than $1,000 in 1966 to soar into the $30,000 range. "Whatever the cost, I'm underpriced," he says, smiling.

Max admits that it would be easy to market himself as a '60s survivor, but not especially gratifying. Spotting a woman wearing one of his old scarves in New York's Hard Rock Cafe one afternoon, the artist can't help but smile. "That's weird to see, after all these years," he says. "It's nice." But unlike '60s rockers who rehash their greatest hits, Max is back with all new material. "I occupy my own space in art," he says. "I've achieved at least as much as Picasso, Matisse and Braque when they were my age." Hyperbole notwithstanding, there's no denying that Max is, in his words, "still a creative entity in the '80s." Just listen to the man who ferries visitors to and from Max's studio. "Up and down, all day long," grumbles the elevator man, wiping sweat from his forehead. "Is this guy getting popular again or what?"