A ghost haunts the Kennedy Center these days and will continue to do so well into July. It is not an American ghost, but that of Czar Boris Fyodorovich Godunov (1551-1605), the Russian Macbeth and the tragic subject of one of Russia's greatest operas.

Rehearsals began last Thursday and will continue through July 6 before taping begins for a complete recording of Modest Mussorgsky's "Boris Godunov" under the baton of Mstislav Rostropovich. This vast project, involving the National Symphony Orchestra and three choruses (the Choral Arts Society, the Oratorio Society and the Chevy Chase Elementary School Chorus) will be a more-than-complete recording. Rostropovich has announced his intention to record "all the music Mussorgsky composed for this opera."

This goal complicates the project, because like many works for the musical theater "Boris Godunov" exists in more than one form. Besides two substantially different texts prepared by Mussorgsky in 1869 and 1872, there is a revision completed by Nicolai Rimsky-Korsakov in 1896, which was for a long time the only version performed anywhere.

Rostropovich prefers the rough-edged but powerful orchestration of Mussorgsky to the glossy sound of Rimsky-Korsakov.

"Rimsky-Korsakov's work was good for the beginning, to make the opera more popular," he says. "But now 'Boris Godunov' is known; now, we need to hear all the details that Mussorgsky put into the score."

The recording sessions, featuring such international stars as Galina Vishnevskaya, Ruggero Raimondi, Nicolai Gedda, Kenneth Riegel and Paul Plishka, will be put to double-edged use -- in a complete audio recording to be issued by Erato and as the sound track of a movie (with visuals to be produced elsewhere, also by Erato) using only the 1869 segments.

For the audio recording, Rostropovich is insisting on completeness. "I don't like making cuts," he said in an interview before beginning rehearsals. "For the movie, they say it won't work if it is too long, so they will do the 1869 version -- no Polish scenes; no love interest. At first, Mussorgsky made his opera like a political fight; then he was told that he had to put in a leading woman's role, so he added the Polish act and the character of Marina. But we won't see that in the movie."

Coming to terms with the historic Boris Godunov is even more complicated than deciding how to perform his eponymous opera. More than three centuries after he seized the blood-stained throne left behind by Ivan the Terrible, Boris is still an enigma -- perhaps more of an enigma than ever before.

For most of the time since his death, Boris has been seen as a kind of monster -- a power-hungry criminal driven by violent passions, but also a religious fanatic who pushed piety over into superstition.

It was taken for granted that Boris was responsible in 1591 for the death of Ivan's son and legitimate heir Dmitri, without which he could not have taken the throne. And he was blamed for misfortunes that befell Russia during his reign, ranging from drought and famine to invasions from Poland and unrest among the Cossacks. "All who suffer the vengeance of heaven believe in their hearts I am guilty," the operatic Boris says in a long monologue. "They lay the blame on me for their sorrows; the name of Czar Boris rouses their hatred."

This is the Boris embodied in the tragedy by Alexander Pushkin (clearly modeled on Shakespeare) that was the literary inspiration for Mussorgsky's opera. Pushkin used such historical sources as were available to him in the 1830s, and he accurately reflected opinion at that time. But one can't help wondering whether he put a bit more enthusiasm into the defamation of Godunov's character because it was a family tradition. In the early 1600s, Pushkins were among the leaders of the opposition to Boris, who complains in Pushkin's play, "I like not the rebellious race of Pushkins."

In the play, Afanasy Mikhailovich Pushkin runs off a bill of particulars against Boris: noblemen imprisoned or exiled; foreign invasions and domestic uprisings; spies and informants working for Boris everywhere; above all, the introduction of serfdom, making it impossible for peasants to leave one master for another.

But the most serious accusation against Boris, the one that haunts him most intensely and precipitates his downfall, is the charge that he is a child-murderer -- that he came to power over the slaughtered body of young Dmitri, and that is the mainspring of Pushkin's play and Mussorgsky's opera.

With Boris in power, everyone naturally avoids open discussion of these rumors, but there is one exception: a small but symbolically vital role called the Simpleton, to be sung in the recording by Nicolai Gedda.

The Simpleton is not only a fool but a beggar. Plying his trade outside St. Basil's Cathedral in the Kremlin, he is molested by a gang of street urchins who steal a kopeck from him. When Boris marches past in procession, the Simpleton stops him and complains about the boys. "Have them killed as you had the little czarevich killed," he begs Boris. When the czar's attendants start to punish the fool for such treasonous talk, Boris stops them and asks the beggar, "Pray for me."

"No, no," says the Simpleton, "it is impossible to pray for Czar Herod." This powerful episode was omitted in later versions of the opera, probably for fear of trouble with the czar's censors. Because of its intense theatrical impact, it is often restored (with no authority from Mussorgsky or Rimsky-Korsakov) in new productions of the opera, and it will be included in the Rostropovich recording.

Even more damaging than the rumors that Boris murdered Dmitri were the rumors that Dmitri did not die and was raising an army to help him take his throne. There was, in fact, a pretender: an unfrocked monk named Grigori Otrepyev (often called "The False Dmitri"), who ran away to Poland, convinced some members of the Polish nobility that he was the rightful heir to the throne and came back at the head of an army.

All this is well established historically. There is today no question that the real Dmitri died in 1591, but Otrepyev won over so many followers that he was able to take the throne after Boris died suddenly and mysteriously in 1605. Naturally, Otrepyev immediately arranged for the murder of Fedor Borisovich, son of the late czar. For good measure, the pretender's minions murdered Godunov's wife.

If Otrepyev suffered the kind of remorse that is a major motif in "Boris Godunov," it didn't last long. His reign was brief, his death mysterious and his successor was Prince Vladimir Shuisky, a vaguely menacing and intensely conspiratorial figure who hovers in the background throughout the opera. Historically, Shuisky was the last czar to hold the throne before the arrival of the Romanov dynasty, which then held power for almost exactly 300 years until the Russian Revolution.

In all this rapidly changing sequence, Boris Godunov seems to have had as legitimate a claim to the throne as anyone else who held it -- enormously more than Otrepyev, who was nothing but an impostor. A revisionist school of historians has cast strong doubts on the theory that he murdered Dmitri, finding evidence that the child's death was accidental.

Eventually, it may emerge that Boris was (at least by the standards of his time) a decent, intelligent man who had a run of ultimately fatal bad luck. But on the stage, in the planned movie and recording, and in the National Symphony's single concert performance on July 6, he will remain what he has been since 1605: a greedy, homicidal monster with a tender conscience. Whether or not it's accurate history, it's intensely operatic material.