When John Baldessari's retrospective "Pure Beauty" opens at the L.A. County Museum of Art on June 27, expect to see several generations of artists on hand for the opening-week events.

For as long as he has been making art in Los Angeles, Baldessari has also been, in a less tangible way, making artists: offering suggestions, encouragement and above all conversation to twenty-something students eager to follow in his footsteps by living a life of art.

Follow they did, with their own gallery shows, museum shows, teaching gigs, and some commercial successes that have at times even surpassed their teacher's.

"There have been many important artist-teachers in Los Angeles, but John has really had a hand in the ascendancy of Los Angeles as a center for artists," says LACMA director Michael Govan. "He's had just as big an impact getting students to stay in L.A. as he did at one point telling them they needed to go to New York."

Jack Goldstein, James Welling, Barbara Bloom, David Salle, Matt Mullican, Mike Kelley, Tony Oursler, Liz Larner and Meg Cranston are just a few of the artists who studied with him at California Institute of the Arts (better known as CalArts) in the 1970s and '80s.

Liz Craft, Mungo Thomson, Karl Haendel, Nathan Mabry, Skylar Haskard, Analia Saban and Elliott Hundley are just a few of the artists who studied with him at U.C.L.A. Many now live in Los Angeles.

But Baldessari, a conceptual artist with a droll sort of humility, is the last to take credit for any of their accomplishments."You never really know where students get their nourishment," he says.

Nor does he glamorize his decision to teach. "I taught because I needed the money--it wasn't a vocational choice," he says. "I was just trying to make it enjoyable for myself, trying to make it as much like art as possible. Maybe that's why it worked."

Born in 1931 in National City, California, he studied art and arts education at San Diego State, getting both his B.A. and M.A. there by 1957. After that, he took a series of teaching jobs: high school, junior high, and community college included. He also taught teenagers in a juvenile deliquent summer camp run by the California Youth Authority, joking that he was only hired for his height--an imposing 6 feet 7 inches.

Then, after two years at the University of California San Diego, he was hired as a faculty member at the newly formed California Institute of the Arts (CalArts) in Valencia. He was no longer really painting (having just cremated his paintings in a rather Duchampian art project) and decided to call his class "post-studio."

"I didn't want to call the class conceptual art because that was too narrow. I think I came across Carl Andre using the phrase 'post-studio' in a magazine," Baldessari recalls.

Post-studio was meant to be flexible in genre and format, he says, with "no assignments and no grades." But he decided to hand out an "assignment" sheet anyway, he says, "just in case anyone needed the structure."

He typed up over 100 ideas for art projects, including one that suggests writing out "I will not make any more boring art" a thousand times. (In 1971, he followed that lesson himself and turned the "boring art" concept into a now-celebrated video.)

Some of his other ideas:

8. Give police verbal description of Baldessari and have him do drawing. Perhaps everyone in class do verbal description.

13. How can a gallery space be used rather than put art objects in it?

69. What art can come from the use of a set of walkie-talkie radios?

74. A film, video tape, etc. that deals openly with a physical flaw of yours (in your estimation.) Make a film called PIMPLE?

99. Art that requires the rental of a Service rather than an Object.

Other "assignments" include putting make-up on pets, designing a secret handshake, and inventing recipes-"they are organizations of parts, aren't they?"

Posing suggestions in the form of questions was typical of Baldessari's teaching style. So was taking his class outside the classroom. In his 1992 interviews with Christopher Knight for the Smithsonian Archives of American Art, he said one of his"tricks" was to put "a map up on the wall, and somebody would just throw a dart and the map, and we would go there that day."

New York painter David Salle writes in the exhibition catalogue of field trips "to the bounty of kitsch art palaces" that made up Los Angeles. During one class they ended up at the Farmer's Market kicking "a freshly plucked chicken" around the stalls. "You get the idea: irreverence veering off into smart-assedness with occasional glimmers of high surrealist poetry," he writes.

The idea was to let students take the lead. As Baldessari says, "For me the sign of success as a teacher was feeling invisible. I wanted to know that I could leave the room and the conversation would continue."

(According to artist Jim Welling, Baldessari actually did let his students fend for themselves when he was travelling: "We had three classes where John wasn't there, but he had a professional stenographer come in and record our conversations." Baldessari doesn't remember the stenographer project but doesn't doubt it either. "That's something I could have done," he says, laughing.)

A similar impulse shapes his artwork, whether his enigmatic text-and-image combinations or celebrated photocollages that block out key body parts like faces. Much as Baldessari refuses to do the thinking for his students, he refuses to complete the dots in his artwork for the viewer, giving them room to draw their own conclusions.

The classroom figures directly into his artmaking in a few ways. In the 70s, he made several pedagogical or pseudo-pedagogical artworks, playfully drawing on classroom motifs and notions of education. In one video, he teaches a plant the alphabet using flashcards. Then there's his video about not making "any more boring art," in which a hand writes the words (again and again) in cursive as if it were a grade-school punishment. Pencils, sharp or dull, intact or broken, recur in his work as favorite pointing devices.

He also works with former students as studio assistants or collaborators. He is now working on two books with former students: one with artist Barbara Bloom and another with Hollywood production designer Naomi Shohan (who, in what Baldessari describes as a full-circle moment, is now working on a film with Kathryn Bigelow, whom he had originally brought to CalArts to teach.)

It's not surprising to find industry talent among Baldessari's alumni, along with various sculptors, painters, photographers, conceptual artists and installation artists. Some artist-teachers are famous for inspiring students who advance their own medium, like Bernd and Hilla Becher and the Dusseldorf photographers who followed them. Baldessari, who tends to mix mediums, is the opposite.

Or, as one former student put it, "He's not in the business of making little versions of himself."