Most museum exhibitions of important art works come together through a relatively formularized process. The organizing curators know what objects are wanted and they know how to locate and obtain them. They simply request loans from private or public collections, or from artists and dealers. The gathering together of the nearly 400 pieces for the Corcoran Gallery's show, "Black Folk Art in America, 1930-1980," was quite a different matter.

When curator John Beardsley and I set out a year and a half ago to put together the first major show of paintings and sculpture by self-taught black Americans, we had only our own hunches and knowledge of five or six such artists to go on. In 1975 I had visited the painter Sister Gertrude Morgan in her New Orleans "mission," a small, white frame house with a front lawn covered with four-leaf clovers and a sign announcing the hours of her preaching services. Morgan sat in her all-white parlor, dressed in white, and made me know I was in the presence of a person of immense compassion, and possibly of genius. In the same year, I had driven a couple of hours outside New Orleans to Patterson, La., to see the elderly and fragile David Butler and the yard around his linoleum house, filled with painted, snipped tin sculptures and whirlgigs. Sister Gertrude has since died; Butler seemed visibly aged, though still miraculously productive, when we visited him in 1981.

The project commenced, based simply on our knowledge of these artists, as well as the relatively well-known Elijah Pierce from Columbus, Ohio; the late George White of Dallas, whose work I had seen in 1976 in the back room of a Dallas art gallery; James Hamton, whose "Throne of the Third Heaven" is permanently on view in Washington at the National Museum of American Art, and the great Nashville stone carver, Will Edmondson.

Starting from this departure point, through a complicated network of collectors, dealers and artists, we learned of and pursued every figure in our newly discovered artistic genre who we sensed might be appropriate to the show. (By no means all of the black self-taught artists whose work we saw are included in the exhibition. We restricted our list to those we felt had attained the highest level of artistic quality.) Of the 20 artists in the show, 11 are living; Steve Ashby, Leslie Payne, Jesse Aaron and Gertrude Morgan died shortly before we began our search. We visited every artist we could find: George Williams and Inez Nathaniel Walker could not be located.

In the weeks we spent in rented cars--from Atlanta to Montgomery, Ala., Nashville to Leland and Crystal Springs, Miss., St. Helena's Island, S.C., to Savannah, and Columbus to Chicago--a series of extraordinary experiences unfolded. Neither of us will ever again have quite the same attitudes about art and artists; about what it means to make art, apart from the "art world" and its sophisticated interconnections, or about the mystery of a single highly developed cultural phenomenon flourishing in the hands of a few unself-conscious individuals, living in total isolation from "high culture."

We first visited Nellie Mae Rowe in her small, cluttered house in Vinings, a village just outside Atlanta. Nellie's amazing output of paintings and scultpures comes from the hands of a strikingly warm-spirited individual. Her humor, even about her own obsession, is irrepressible: "Somtimes," she told us about her compulsion to paint, "I even get behind in my washing." When I asked her if she were interested in the art she had recently seen on a trip to New York, she looked at me with a slight smile, considered the question carefully, and finally said, "I look at my own art."

Mose Tolliver met us at the front door of his old wooden house in Montgomery, leaning forward heavily on his crutches, plainly glad to see us. The walls of the big bedroom/living room/studio where we all sat to talk were covered with Tolliver's paintings on wood. Tolliver's wife and various children and friends came in and out. Tolliver became less and less shy and funnier and funnier as he explained, often with a sly sense of double-entendre, what his sometimes bawdy and always dstinctive paintings were about.

In Mississippi we spent a day in the small Delta town of Leland, spawning ground of many black blues musicians, with James "Son Ford" Thomas, sitting on his bed, talking mostly about his career as a composer, singer and guitarist, listening to him play, and later going with him for a beer at the local bar. James Thomas' unmistakable gift, both as sculptor and musician, and his profound personal charisma, obviously attract everyone within range; we could clearly feel the esteem in which he is held in his community.

In Savannah, we spent a long morning in Ulysses Davis' barber shop, watching him cut hair, and selecting for our show from his dozens of carved wooden sculptures and reliefs. The 38 heads of American presidents were lined up in a row on two long shelves; Ulysses showed us the handmade tools he uses to carve them, and talked about himself a little. He said he loves cutting hair, and he loves carving wood.

One of the most awesome personalities we met in our odyssey is Elijah Pierce, a former preacher and barber who lives in Columbus, Ohio, and continues to make beautiful painted-wood reliefs and free-standing carvings. We spent an afternoon sitting with Elijah on his front porch: various neighbors and friends, paying their respects and even asking for spiritual advice, stopped by while we sat there. The 90-year-old Elijah has the distinctive presence of a highly self-knowledgeable and serenely observant man who has managed to create not only an important body of art works but a remarkable life. He related to us several electrifying anecdotes about his life and times.

The artists we've come to know in preparing for this exhibition have taught us a great deal. Their eccentric, always humble houses and yards are somehow in themselves strangely moving and resonant as an American art form. The artists are almost without exception among the sanest, funniest and most resourceful people I have known.