Cambridge, Mass. — Exactly when audiences will be able to see Robert Wilson's "the CIVIL warS" in its entirety is anyone's guess. Written in five acts and 15 scenes, the complete piece will take 12 hours to perform. It was supposed to be done at the 1984 Olympics in Los Angeles, but the Olympic Festival ran short of money. It was then scheduled to be performed this fall in Austin as part of the Texas sesquicentennial, but the calamitous turn in the oil business forced the cancellation of this along with a number of other projects.

Up to this point "the CIVIL warS," whose subtitle is "a tree is best measured when it is down," has been seen in bits and pieces. Fortunately the pieces are far more engaging than many works seen in full. As part of his overall scheme, Mr. Wilson conceived of a series of entr’actes, like the interludes between the major star turns in a vaudeville show. Because they are to serve as the "joints" between the other parts, Mr. Wilson calls them "The Knee Plays." They are also referred to as the "The American Section," because they have been done here, but also because the musical score was composed by David Byrne.

Though "The Knee Plays" are intended to be interspersed between major segments of the full 12-hour version, Mr. Wilson had the idea of stringing them together for a single evening of theater, which had its premiere a couple of years ago in Minneapolis. The current production, scheduled to run through this weekend, has been mounted at the American Repertory Theater as the first stop on a 10-city tour of the U.S.

There is no question that they work as a separate, successful evening of theater. In fact, I can think of no better introduction to the extraordinary world of Mr. Wilson's vision than to see "The Knee Plays." The unmatchable images, the haunting mystery, the inventive juxtaposition of unlikely elements that characterize Mr. Wilson's stage productions are here in profusion. At the same time, this is probably the most accessible work Mr. Wilson has produced. Unlike the complex five-to-12-hour epics he has challenged audiences with in the past, "The Knee Plays" lasts only 90 minutes; divided into 13 sections, each scene lasts an average of about seven minutes.

The highly stylized nature of the piece is evident from the opening moment. Except for an abstract tree formed by latticework squares in the shape of a T, the stage is bare. The outline of the stage forms a wide, rectangular picture frame around a brightly lighted, blue-gray background. One by one, the black-clad performers in the Les Misérables Brass Band, which provides music for the evening, walk on stage with slow, measured steps, making two, precise right-angle turns to take their places at the side of the stage.