Fearless Wendy Knox, artistic director of Frank Theater, searches out plays thick with social and cultural issues and finds their hearts in often unconventional and powerful productions. Marc Blitzstein's 1937 folk opera, The Cradle Will Rock, is no exception.

Knox not only chose a rarely-performed period piece that is sledgehammer pro-union, but she stages Cradle on a vast second floor section of the semi-derelict Sears building, a giant distribution facility that has stood empty for years. The setting lends itself to a show that waves the flag for the beleaguered working man. Set designer John Beuche blends the rough concrete walls, large WPA prints and selected clutter of industrial hardware, gathered from the building's working life, to create a fitting atmosphere for the opera. Even the entrance, via a loading dock, the climb up bare steps and the echoing slam of an industrial fire door as you enter the performance space, add to the play's resonance.

Blitzstein's book, clever lyrics and Kurt Weill-like music tell of Steeltown USA, a town that is run by Mr. Mister, a steel-willed magnate, bent on amassing immense wealth from his steel mill at any cost. He buys and compromises the town's self-satisfied middle-class citizens, is ruthlessly anti-union and arranges for agitators to perish in explosions or "fall" into ladles of molten steel. On this night, a big union drive is underway. An inept policeman hauls Mr. Mister's conservative, anti-union Liberty Committee into night court, mistaking them for union agitators. Also in night court is Moll, a starving prostitute, but as each Liberty Committee member is booked and his corrupt ties to Mr. Mister are revealed in flashback, it becomes clear that they are just as guilty of selling themselves as she is.

Blitzstein wrote his characters as types - caricatures that are so black and white, they could step from the pages of a comic strip. Knox runs with this idea and directs Cradle in a style of arch surrealism. Movements are styled and exaggerated, and Kathy Kohl's wonderfully bizarre costumes wildly inflate each bad character's type, so that fawning university president Prexy (Jonathan Peterson) wears the baggy pants of a clown and has a fuzzy tuft of ginger hair rising from his bald pate, and sexually manipulative Mrs. Mister dresses in glittery, knock-you-off-the-catwalk fashion and doesn't wear the same outfit twice. Only sympathetic characters, most of them dirt poor, are dressed in clothes with which you might identify.

Knox opens Cradle with theatrical panache. On a dimly lit space, you hear an off-stage cascade of dropped metal rods, the grind of heavy machinery that sounds like a panting monster, and raised voices, talking of a strike. The motley group of the Liberty Committee, moving in weirdly gestured motion, spills on stage from between the audience seating, which lines two sides of the space. It's a surreal start, and all that follows is just as weird and compelling.

A cast of 18 sings and acts the folk opera's 26 roles, and Knox has put together a remarkable ensemble of performers. Six of the male roles are played by women, and Maria Asp has great fun with this gender bending. She plays a Cop and pushes male mannerisms to amusing limits; she swaggers, chest and belly pushed out, and scratches her crotch with her nightstick. Asp also plays the shady thug Bugs, then, with versatility, switches to become earnest Ella Hammer, the wife of the worker who "fell" into the ladle. Vera Mariner entertains as the weak Reverend Salvation, and Maren Ward relishes her role as macho Professor Trixie.

Knox pulls strong performances from all members of her cast, too many to acknowledge individually. Outstanding among them is Ruth Mackenzie as Moll. Her songs, sung in a voice of rich warmth, are meltingly sad. Gary Keist plays Dick, another cop, as a true dick, and his Larry Foreman is all wholesome charisma, the noble working man straight out of social realism. Molly Sue McDonald fills Mrs. Mister with wicked flair, and Alan Sorenson convinces as the cigar-chomping baddie, Mr. Mister.

Natalie Hart has choreographed a hilarious campy duet between artist Dauber (Eric Sumangil) and concert performer Yasha (Patrick Bailey.) Marya Hart leads the five member onstage music ensemble, and Michael Kittel improvises strong creative lighting in a difficult space.

As a people's opera, Cradle has particular resonance in a time of strong anti-unionism and corporate malfeasance. Knox's playful yet fervent production held me fascinated throughout its intermissionless, one hour, 40 minute length. So, pull on those work boots and go.

The Cradle Will Rock October 3 - 26. Thursdays, through Saturdays 8:00p.m. Sundays, 2:00 p.m. $5 - 20. Frank Theater, The Former Sears Building, 900, East Lake Street, Minneapolis. (Enter on 10th Avenue South, across from parking lot.) Call 612-724-3760, or www.franktheatre.org.

Also recommended: Edward Albee's A Delicate Balance at the Jungle Theater. Strong acting, intelligent direction and a superb set distinguish this production.

A Delicate Balance until November 2. Wednesdays, Thursdays and Sundays 7:30 p.m. Fridays and Sundays 8:00 p.m. Matineés Sundays 2:00 p.m. $19 - $30. The Jungle Theater, 2951, Lyndale Avenue South, Minneapolis. 612-822-7063.

- Elizabeth Weir