Last year, Tom Stoppard's (and Andre Previn's) "Every Good Boy Deserves Favour" was brilliant. This year, it's a rerun.

That doesn't mean that it is not still brilliant, but a lot of its brilliance is one of the kind that works only once, only when it comes with the shock of surprise. Those who have not yet seen it can expect a good evening's entertainment with occasional, undeveloped hints of deeper substance.

"EGBDF" is a play that pirouettes nimbly around some of the central and most anguishing questions of our time but fails to answer them. It is hard to blame Stoppard for this. If he could solve the problems he raises -- which range from the nature of reality and sanity to the relation between citizen and state -- he would be wasting his time writing plays; he should be ruling the world.

For those who have not yet seen it (and certainly should), "EGBDF" takes place in a Soviet insane asylum. Its two central characters are both namem Ivanov, and they share a cell -- or a ward; what you call it is a question of ideology.

One Ivanov (Rene Auberjonois) is authentically insane; he believes that he is the proprietor (and the triangle player) of a symphony orchestra. There is, in fact an orchestra occupying the stage of the Kennedy Center Concert Hall, with three bits of scenery (a two-bed cell, a schoolroom and a psychiatrist's office) inserted among the musicians. Sometimes, the orchestra is "imaginary," making the motions of playing but no sound. Most of the time, it is playing Previn's music (with some assistance from the "1812 Overture.")

The other Ivanov (Eli Wallach) is sane by American standards but insane in Soviet terms; he is in an insane asylum because he has been insisting publicly that sane people are put in Soviet insane asylums. He cannot hear Auberjonois's orchestra, and for a good part of the evening he is the only one in the Concert Hall who cannot. That may be a comment on the sanity of the audience.

Ivanov-Wallach had become a problem to the Soviet authorities because he is or a hunger strike and his case is known to the outside world; they wouldn't mind if he died, but only if he died quietly and anonymously. They are looking for a graceful pretex to release him and the director of the institution, Col Rovinsky (played by Carl Low, who bears a remarkable resemblance to Arthur Fiedler) finds one based on the fact that both men are named Ivanov.

"Do you believe that sane people are put in mental hospitals?" Rovinsky asks Ivanov-Auberjonois -- and, of course, he doesn't. Then he asks Ivanov-Wallach whether he thinks he has a symphony orchestra, and gets (grudgingly) a negative response. "There is absolutely nothing wrong with these men," he tells the psychiatrist. "Get them out of here."

This sequence (raising serious questions and answering them with a dramatic pun) is not quite the cop-out that I thought it was the first time I saw "EGBDF." It underlines the point that a strong individual ("rigid" is the word used in the play) can stand up to a totalitarian government and make it find face-saving solutions -- and the recent history of Soviet dissidence indicates that this is true, at least sometimes.

But it does symptomatize a problem with the play. Stoppard cannot resist one-line brilliance, plays on words, the kind of jokes that work once -- jokes like calling the harpist "plucky" or saying that "the bass drum is in urgent need of a dermatologist." Hilarious the first time, it is deja-vu the next time, unless you are happily gifted with amnesia, in which case it will be brilliant again.

Previn's music is also largely dejavu, but in his case it is intentional and it works. He has written a score largely in the approved Soviet style of "socialist realism" -- the kind of music you might expect from a composer with a name like Shostakofiev -- and it is atmospherically right in the brooding melodramatic sections of the play, sometimes hilarious when the orchestra is commenting on the stage action. The orchestra, conducted by David Gilbert, is made up of Washington free-lance musicians and they give a good account of the score.

"EGBDF" will be at the Kennedy Center through Aug. 19, and those who have not seen it before or who enjoy reruns should try to see it. Because of its unusual casting requirements (how many plays have a whole orchestra in the cast?) it is not likely to be rerun again in the near future. CAPTION: Picture, Rene Auberjonois, left, and Eli Wallach in "Every Good Boy Deserves Favour"; by Gerald Martineau -- The Washington Post