CONSIDER A Midsummer Night's Dream as a gamut for the stage, a series of isometric exercises for a theater company. In its roughly 2000 lines--far shorter than a Hamlet or a Lear--are scenes of courtly reserve and natural abandon, metaphysical mystery and droll stupidity, gathered up and joined behind the proscenium of Shakespeare's florid verse. Where a play like Troilus and Cressida yokes different forms of theater violently together, Midsummer Night's Dream carefully weaves them in, under, and through each other--thus the shimmering, unsettled brilliance it displays in the hands of a good director. It's a fine opportunity for a repertory company to flex its muscles.

But this Dream at the Loeb goes far beyond technical proficiency or dramatic virtuosity. The play demands total ensemble work not just for the sake of the number of major roles it contains but for the revelation of its multiple meanings, and the American Repertory Theater (ART) provides a group of performers with vocal skill, physical agility, and intellectual acumen. They present in transcendent clarity--sometimes in neon signs--the question at the heart of Shakespeare's play: how to create marital tranquility out of the irrational workings of love. Most of the refinements and elaborations director Alvin Epstein introduces serve not to obscure but to subtilize the issue.

Foremost among these is Epstein's appropriation of Henry Purcell's score for The Fairy Queen, with chorus, soloists and instruments of the Banchetto Musicale, as a means both to lengthen and to enrich Shakespeare's play. The backhanded slap at Mendelssohn's romantic score, with its pianissimo fairies and ebullient wedding march, makes clear even before the lights go up the director's vision of A Midsummer Night's Dream: counterpoint over harmony. If the music doesn't bring that message home, Epstein has added a brief masque to accompany the overture: before a Paolo Uccello-like tapestry, the helmeted figures of Theseus and Hippolyta have it out with swords (Hippolyta wins).

With less care this discord-first interpretation could turn the Dream into a rowdy cockfight, with lovers, parents, fairies and rustics tussling through scene after scene. But Epstein draws nearly all of his conflict from the text--except for an amusing pre-marital spat between Theseus and Hippolyta that makes some dramatic sense but seems only marginally present in Shakespeare's original. Everywhere else, the conflicts in this production neatly fit into a world thrown out of kilter by the feud between Oberon and Titania, the presiding deities. The explosive initial entrance of the lovers and Egeus, grunting and panting, or the encounter between Puck and one of Titania's fairies, each bristling, spitting and snarling like primates in some mating ritual--scenes like these present a quarrel-lust that grips like a disease and only passes after the transformational night in the forest.

With Purcell's music lending a touch of formal majesty, the performers move from discord to concord in a progress that sinks deep into the layers of Shakespeare's meanings, to emerge restored and invigorated. Stage movement as much as language becomes a spade they use to unearth poetic ambiguities, in several mimes enacted to bits of Purcell's score: while a soprano sings a mournful aria, Stephen Rowe's Demetrius and Lisa Sloan's Helena wander about in a ghostly love-dance, with Helena reaching for and grasping Demetrius just as he turns away; after the night of illusion in the forest is over, and the lovers are rubbing the sleep and dreams from their eyes, they recap the confusions of their double-love-triangle in a whirlwind mime before running back to the city.

Tony Straiges's set does more than its share to point up Epstein's intent. If the battle-tapestry that represents the court overstates the theme of conflict, its one-dimensionality perfectly sets the city off from the wood; as the tapestry rises it reveals no lush, enchanted garden but a Greenwood of primal forces, spaciously expanding sideways and upwards towards the silvery moon--a stark, haunting vision of nature largely unconcerned with or uninterested in man.

The characterization of the upper and lower orders of the fairy-world matches. Kenneth Ryan's Oberon pompously barks his lengthy speeches as if entranced by their weight; Carmen de Lavallade's Titania flexes her body in superhuman ways and says more with it than most performers manage with the help of Shakespeare's verse; the quartet of fairies in her train--dressed in skintight body suits, adorned with tails and extended fingers--is menacingly inhuman. Their lullaby for the sleeping queen, miles distant from both Mendelssohn and Purcell, sounds exactly like a chorus of watchful insects.

Most alien of all is Mark Linn-Baker's Puck, a nasty demon who sticks his tongue out and rasps at friend and foe. His satyr's outfit and white makeup don't distance him from humankind nearly so much as his utter indifference to pain and suffering in others. When Oberon orders him to undo the effects of his mistake on the lovers and to anoint Lysander's eyes with the potion that will restore his love for Hermia, he nearly fouls up again and gives Demetrius the charm. He says "Lord, what fools these mortals be!" spitefully, not compassionately, and sounds like he means it.

The sextet of "rude mechanicals" who wander into the forest to rehearse their play intrudes on this inhuman enclave like visitors from another dimension. Their antics, delivered by the ART actors with gung-ho spirit and the precision of acrobats, form a haven of the familiar in Epstein's inhospitable forest; yet even they become possessed, reacting to Bottom's "translation" by careering across the stage in hops, sprints and tumbles while the musicians play one of Purcell's country dances. The sorcery of the wood finds little purchase on their "hempen homespun" minds, but gets at then anyway through their bodies.

Not the least marvel about this Dream is Epstein's ability to draw humor from the play even as he is interpreting it in an essentially solemn way. We expect the rustics and their "Pyramus and Thisbe" to be a comic staple, and certainly John Bottoms's eponymous, stage-struck Bottom, Jeremy Geidt's paternal, befuddled Quince, Max Wright's scallion-chomping Flute and their cohorts dig up laughs you'd only guessed at, reading the play. But the young lovers, too, keep their scenes from bogging down into indistinguishable, interchangeable laments: Sloan's strong-willed and-armed Helena gets a hapless Demetrius into a half-nelson, and literally dogs his path with a graphic spaniel imitation; Eric Elice and Marianne Owen as Lysander and Hermia separate "as may well be said becomes a virtuous bachelor and a maid" before they fall asleep, roll towards each other and exchange places before waking up. Even Linn-Baker's alien Puck adds comic touches, hopping to his sing-song tetrameter or grimacing with impatience at Oberon's bombast.

BUT HUMOR in Epstein's production serves as a counterpoise to, not a remedy for, the harshness of nature: both moods coalesce under the spell of Purcell's music into an almost consecrational celebration. That's appropriate for A Midsummer Night's Dream's nuptial blessing in dramatic form, and the consecration applies at least as much to the new-born theater company as to the three couples onstage. The music, with its rich ornamentation, dark coloring and sprightly rhythms, captures just the same many-hued atmosphere as Epstein's staging. Unfortunately, it also introduces the only significant flaws in the Loeb production. The lyrics to Purcell's arias and choruses are often poetically inferior ot Shakespeare's verse, and sound rude, out of place. The stiff movements of singers from the Banchetto Musicale onto the stage--apparently to serve as a sort of Greek chorus as well as a musical one--has the same effect, clashing with the actors' finely choreographed and executed motions. The singers would be better off remaining where they begin, arranged antiphonally in front of both sides of the Loeb proscenium.

You have to squint hard to find inconsistencies like these, though, and aurally if not physically the music works. More curious and ironic is the presence onstage of Robert Brustein, ART's director and a philosopher of the theater in his own right, as Theseus, that unrepentant skeptic with no faith in drama or poetry. This, after all, is the character who delivers the famous speech lumping lovers, poets and madmen together as creatures of imagination, flighty and deluded:

The poet's eye, in a fine frenzy rolling,

Doth glance from heaven to earth, from earth to heaven;

And as imagination bodies forth

The forms of things unknown, the poet's pen

Turns them to shapes, and gives to airy nothing

A local habitation and a name.

It requires a powerful imagination indeed to suppress an involuntary wry smile when you hear Brustein's Theseus remark, of actors, "The best in this kind are but shadows." Perhaps--just as Shakespeare's play is "only" a dream. At the Loeb, both shadows and dreams seem, if only while the curtain is up, to take on a radiant and tangible form all their own.