The performance by the Merce Cunningham Dance Company at the University of Maryland's Tawes Theatre last night was labeled, simply, "Event." Seldom has such a small word expressed so much of artistic significance. It was an eventful occurrence in a multiplicity of ways, not the least of which was the return to the Washington area of the Cunningham troupe after an absence of nearly a dozen years. In turn, this meant a firsthand reacquaintance with the work of one of the century's master choreographers, and a vibrant reaffirmation of his mastery. Virtually the whole foundation of what we now recognize as contemporary dance esthetics originated with Cunningham, in his rejection of narrative, symbolic or psychological content, and his insistence on pure movement as the core of the dance experience. Many have since gone beyond Cunningham's own esthetic parameters, but they've done it by standing on his shoulders, and we have yet to encounter his peer -- among his successors and disciples -- in sheer creative fecundity.

The audience gave Cunningham and his present troupe of 13 dancers a fittingly resounding welcome at the end (there were some whoops of enthusiasm that out-whooped anything in recent memory), but their numbers amounted to perhaps 600 in a hall that holds more than twice as many. Why more didn't show up for this rare area appearance of one of the indisputable "greats" of dance is a mystery; tonight's repeat performance affords one more chance not to miss out on the unmissable.

An "Event" is one of Cunningham's characteristic inventions -- it's a composite, a montage, if you will, of fragments of past work, sometimes entire pieces, sometimes newly created segments, all laced together in seamless continuity and danced without break over a span of about 90 minutes. A Cunningham "Event" is hence something like a palimpsest -- one of those canvasses that have been painted over many times, layer upon layer -- except that all the layers are visible at once. It's an instant retrospective, history in the present tense.

Last night's "Event" rebounded with quintessential Cunningham images and stratagems. Echelons of dancers would waft onto the stage like leaves in a fall wind, cohere into symmetrical arrays, and instantly disperse into seemingly random clusters. A pair of dancers mimicking each other's moves in exact unisons or parallels would imperceptibly shift into counterpoints and oppositions. Flurries of hops and bounds and twists would devour one portion of stage space, while dreamily slow unfoldings and poses occupied another. Sometimes dancers simply stood waiting in bemused attention at the rear or sides, like jets queued on a runway for takeoff. Yet each new sequence of action overlapped with the one preceding it, and often several played themselves out at different tempos and energies at the same time.

One section, some of us were informed beforehand, was just choreographed for this occasion; Cunningham calls it "Intermission," and though the "Event" never halted, in this midway passage the dancers strolled casually on stage, struck poses, relaxed supine on the floor, did warm-ups -- just the sort of stuff dancers do while audiences are taking a break in the lobby. Another highlight of the "Event" was the penultimate solo for Cunningham himself -- at 62, no longer quite a technical virtuoso, he's still amazingly strong and limber, and capable of a kind of gestural subtlety, impishness and imagination that remain unique. The company, though, is looking superbly trim and cohesive -- it's amazing that with so many relatively new members the troupe projects the Cunningham sensibility as if with one mind and spirit.

That sensibility is a demanding one by any yardstick. In economy, clarity and even vocabulary of steps and shapes, Cunningham is at bottom a classicist, but it's a classicism of quirks, eccentricities and lightning changes of attack and direction that put the dancing body to a severe test. The present-day Cunningham troupe passes with flying colors; beautifully cultivated, alert to each other and to the whole choreographic context, they make Cunningham's intricate abstractions into a poetically evocative tapestry of ceaseless fascination.

As always with Cunningham, the costumes were simple body tights in contrasting groups of color; the rhythmically inventive lighting scheme was by his longtime collaborator, filmmaker Charles Atlas; and the tense, sparse, electronic soundscape, running along its own separate track, was executed by David Tudor and Martin Kalve.

What gives Cunningham's choreographic rhythms and densities and structures their sense of organic continuity and life, when the work of lesser artists working in similar modes so often seems arbitrary or inert, is largely a mystery -- one of the secrets of dance creativity that no one can quite explain rationally. The experience of seeing the Cunningham troupe in action, however, is self-verification of the power of his vision. Watching a Cunningham "Event" on a proscenium stage, in contrast to its more usual habitat of an open space or studio, doesn't quite give the viewer the sense of sharing the dancers' space and energy that is otherwise possible. But we'll take it any way we can get it, with the fervent hope the next opportunity won't be long in coming.