It is always astonishing to hear just how different two recordings of a single work can be, a fact brought home by the recent release on Columbia (M2 33594) of Schönberg's Moses and Aaron, conducted by Pierre Boulez. Günter Reich's version (Philips 6700 084), released last year, emphasizes the declamatory aspect of Schönberg's textual settings, and is recorded with a clarity that delineates each instrumental line, but the end result, though theatrical, lacks a feeling of musico-dramatic unity. Boulez's version could not be more different: since the sound is less close and immediate, one hears shifting instrumental textures rather than individual nuances; the sprechgesang is more sung than spoken, so that the work sounds expressionistic rather than serialistic; and the whole is integrated into an organic synthesis of music and drama that is quintessentially operatic.

Some delightful minor gems by Mozart are offered on two Philips discs. One (6700 097) is devoted entirely to Zaide, an early Singspiel, performed with grace and charm by a cast which includes Edith Mathis and Peter Schreier. The other disc (9500 011), an irridescent reading of The Impresario and Lo Sposo Deluso, is crisply conducted by Colin Davis and features some captivating singing, especially by Leiana Cotrubas, whose limpid vocal quality is particularly well-suited to music of this period.

Miss Cotrubas's singing is equally marvelous in the first recording of Haydn's comic opera La Fedeltd Premiata, directed by Antal Dorati with Frederica Von Stade, Luigi Alva, Lucia Valentini, and Alan Titus (Philips 6707 028). The pastoral plot is silly beyond belief, but Haydn's music is so graceful, animated, and cheerful—qualities which cast, orchestra, and conductor realize to the utmost—that the opera is enjoyable from start to finish.