How lucky we are that the two greatest pianists of their generation, Murray Perahia and Radu Lupu, are firm friends and that they have collaborated in recording two pieces that are arguably the most successful examples of their respective genres (the Schubert is for piano duet; the Mozart for two pianos). Whether it is in the perfectly crafted busy activity of the Allegro con spirito first movement of the Mozart or the introspective and soulful depth of the Schubert, the players find a unanimity of vision. One is not so much conscious of dialogue-like interplay, but more of them blending to play as one instrument.

The fine CBS recording has entirely captured the subtle inflections of detail, especially in the artists' irreproachable balance. Taken from a live performance at The Maltings, matters of ensemble, which usually defeat the Mozart Sonata, are judged to perfection. After the double bar of the slow movement Lupu and Perahia become lost in each other's thoughts and the effect is overwhelmingly beautiful.

I hardly dare to quibble about a point, but I feel the Largo section in the Schubert is a trifle slow; what works in live performance does not necessarily sound convincing on record. But it is wonderful to hear both the primo and the secondo parts shaped with such care. The fugato and development sections are neither hard-driven nor thick-textured, though clarity is never out of balance with artistic inspiration. I hope that Perahia and Lupu will find time to record Schubert's Grand Duo Sonata as well.