Besides being one of the best modern recordings of this masterpiece about a Macbeth-like czar who murders his way to the top, this five-disc set (sold for the cost of three) presents the opera both in its original 1869 version and in its 1872 revision, side by side. The former is clearly not finished: it needs more scenes (key characters have little stage time), and the ones that do exist don't always make their full dramatic impact. However, there's much brilliance even in nascent form, particularly with the composer's discreet breaks with traditional, functional harmony a full 30 years before Debussy. Even passages that sound inept do so eloquently, thanks to Valery Gergiev's seemingly telepathic rapport with Moussorgsky's psychologically penetrating dramaturgy. Key roles are often double cast, which gives vocal and interpretive variety and shows off just how rich the Kirov Opera is in bass voices. I prefer the earlier Boris (the lighter-voiced, more nuanced Nikolai Putilin) to the beefier Vladimir Vaneev in the later version. The later Grigory, Vladimir Galusin, shouts a bit but in a text-attentive way; besides, his character (the pretend czar) is likely to go for bombast. Borodina's Marina is relentlessly imperious and not sufficiently seductive--the one minor problem in this fine, studio-recorded set that signals a great sonic improvement over Kirov's more fatiguing outings in the Mariinsky Theatre. --David Patrick Stearns