With more than 200 objects and several snazzy special installations, the show is the joint production of five MFA experts (Gerald W.R. Ward, Pamela A. Parmal, Sue Welsh Reed, Gilian Ford Shallcross and Carol Troyen). That is not unusual for an exhibition of this scope. What is surprising, however, is that this is the first major show devoted to American folk art in the museum's history.

The museum was handed a great collection of folk art (along with nonfolk material) in its tripartite, encyclopedic M. and M. Karolik American Art Collection beginning in the 1940s. Maxim Karolik continued donating pieces after his wife's death into the '60s. Now many of these iconic works are being shown along with some superb loans and a handful of recent acquisitions by the museum.

Folk art was considered too humble and homemade to be anything but second-rate until the early 20th century, when modern artists and collectors awakened to its power. Folk art's spare forms, brilliant use of patterning and design and direct emotional appeal have made it a hot collecting area for years. It's a treat to see so many of the museum's treasures at last.

Because folk is usually defined by what it's not -- not high style, not by the professionally trained, etc. -- the show starts off with a few examples, like a stunning Baltimore album quilt, to get viewers acclimated before settling down to five loose thematic categories of work -- "Family Album," "Birds and Beasts," "Land and Sea," "Bountiful Harvests" and "God and Country."

In "The 18th Century," an imposing life-size pair of portraits, Reverend Ebenezer Devotion and his wife, the first commission of then-23 year old Winthrop Chandler, are on loan from the Brookline Historical Society. The flattened and simplified form of the Reverend meets your gaze straight-on, a completely dignified rock-solid presence. His wife's likeness is sure, but her dress, a cascade of fabric and lace that's a tribute to their social standing, almost steals the show. No wonder Chandler became the most successful portraitist in northeast Connecticut. He's an important artist and well represented throughout the show, but perhaps never more spectacularly than here.

A chest of drawers from a private collection stamped with rectangular designs in white, orange and green on a dark background is another standout. Its decoration is completely modern in feeling and would make a handsome addition to most contemporary apartments. A highlight of a selection of Pennsylvania German fraktur is a birth and baptismal certificate by Georg Friedrich Speyer with a wacky pair of paddle-handed, bird-headed mermaids.

The largest (almost 7 x 8 feet) canvas by the noted Massachusetts painter Erastus Salisbury Field, Joseph Moore and His Family (ca. 1839), is one highlight of the "Family Album." Moore was a dentist and hatter, who sits proudly before a mirror with his family around him.

Instead of simply presenting the works as esthetic objects, the museum has opted to put selected pieces into a cultural context. For the Moore painting, Moore's chairs and bits of his wife's jewelry, like her mother-of-pearl belt buckle, seen in the painting, and his tools and other personal items are displayed nearby, making the visitor feel closer to the lives of the sitters.

Another notable multiple portrait is The Lincoln Children (1845) by Susan Catherine Moore Waters, one of the few professional women portrait painters. Its three little girls, all pinks and whites, have at their feet a strange but amusing puppy, a fruit basket and potted plants

Nearby is a painting of a trio of little black girls, Three Sisters of the Copeland Family (1854) by William Matthew Prior. An abolitionist himself, Prior ran a Boston painting shop and had many African-American clients. His forms are sparer than Waters' and pressed closer to the picture plane. Prior uses color subtly, weaving reds throughout and using the youngest girl's red-and-white-striped leggings to pull the painting together.

There are three versions of Ammi Phillips Girl in Red with a Dog, but only one Zedekiah Belknap Girl in White with a Cat (1840), looking sweet in her lace-collared dress here, another impressive loan from a private collection.

A special section is devoted to more academic pieces in several media compared with similar folk works. At a glance, it demonstrates the sophistication of pieces once considered naive. A Boston cleric by Gilbert Stuart, for example, pales next to a preacher from Troy, N.Y., by Ammi Phillips, with his severe black suit sandwiched between a stretch of green wall and a red pulpit cushion.

In "Birds and Beasts," contextual groupings include metal and wood weathervanes presented against the roof of a barn and a mirror-pond with floater decoys and stick-up decoys. Among the floaters, a seemingly quizzical redhead drake (1910-15) by A. Elmer Crowell is a knockout. A carved and painted red fox by an anonymous artist (late 19th century) prowls the perimeter.

There's a large number of crude but vigorously carved and painted chickens, some eagles and a lion by the possibly German-born Wilhelm Schimmel (1817-1890). Schimmel, who swapped carvings for booze, was a famous drunk in Cumberland County, Pa., but is now remembered as an extraordinary sculptor. He's so famous, his work is often faked.

Based on a print is Meditation by the Sea (1860s), an iconic work by an unidentified artist. It's one of a clutch of wonderful paintings in "Land and Sea." In the same area, Celestine Bacheller's pictorial crazy quilt from the last quarter of the 19th century presents 12 different views of coast near Lynn, Mass., in pieced and embroidered silk. An acquisition from last year is a charming railroad quilt with touches of red to enliven its blue and white design. Textiles of all sorts really shine in this show.

Georgian Harriet Powers is known to have made only two quilts; both are extraordinary. Her Bible Quilt from around 1895, commissioned by women who had seen an earlier work of hers, is the focal point of "God and Country." Fifteen pieced and appliquéd squares depict scenes from the Bible, like Jonah and the whale, or natural phenomena, like meteor showers. For company, it has an Edward Hicks Peaceable Kingdom and an Erastus Salisbury Field Garden of Eden, and a host of schoolgirl memorials in a variety of media.

A mini-installation looks at folk art admired and collected by modern artists, like Charles Sheeler, Elie Nadelman, Marguerite Zorach who absorbed the stripped-down forms and clean lines of folk art, and compares it with their own. A William Hunt Dietrich black cut-paper of a Circus Girl (1920s) riding two horses is paired with a running horse weathervane. A Marsden Hartley austere and powerful portrait of Lincoln is presented beside a more decorative, although equally pared down Mr. Tiffin of Kingston, New Hampshire (1820) by A. Ellis. The comparisons are not always as exact as possible, but you get the idea.

This is a big, glorious show. There's only one thing missing -- a catalogue equal to the exhibition. The museum has published about 60 works from its own collection in "American Folk" in hardcover ($40) and soft-cover ($24.95) to accompany the show. It's a start, but where are the rest of the pieces, especially those great loans?

Maybe the museum just wants to force everyone to get a ticket and see everything in person. "American Folk" is certainly worth the trip.

The show is on view through Aug. 5, 2001, by timed ticket entry. For advance tickets, call (617) 542-4632.