Sessions music is nowhere near so 'difficult' as such a reputation would suggest. His first Sonata, for example, is lyrical, bouncy almost, sunny and immediate. Holzman plays its single movement - it lasts almost a quarter of an hour - with measured attack, never lingering nor yet rushing. He persuades us that there is much to be squeezed from its at times busy sounding full and rich passages. Holzman invites us to glance back to Ives … and even to Brahms! … through the eyes, perhaps, of Carter.

Like Messiaen's, the voice of the third sonata (from 35 years later and fully serial) is rich, packed and dense. Yet Holzman draws out Sessions' assuredness. The composer was not one to muse aloud or foist his experiments on us as he went along. This music is as carefully pre-considered as anything by Webern or Bartók. Its compelling beauty is spare in the first movement; yet we are teased, almost, by the changes in pace and texture. As it goes on the sonata becomes wilder and more expansive. Yet it never loses a classical beauty of melodic line for all the furious counterpoint and 12-tone attack. Holzman stays in perfect control without a hint of woodenness. He is an ideal pianist for this repertoire: he has not only an amazing technique (and at least 20 fingers); but his sensitivity to the inner structure of the music is sure and revealing without being overly 'pianistic' as such.

Ralph Shapey came from a different world, in some ways. Proletarian to Sessions gentry, he was most at home in the Abstract Expressionism of the New York scene. Shapey studied with Stefan Wolpe but was as close to Feldman (and even Cage) in his interest in fragmentation, pulsing extracts of sound surrounded by silence as a valid way to move a work forward. Holzman is - again - completely in accord with this idiom.

Mutations, Mutations II and 21 Variations have in common an interest in tension and withheld resolution. There is even more of Webern in the condensed nature of pieces like Mutations [tr.5]. It dictates its own terms of reference and rules. In that sense it needs to be played almost as an introverted and highly refined and concentrated interlude. And so Holzman plays it - yet somehow as an inevitable complement - to the rest of one's day - whose purpose and context can neither be ignored nor forgotten. Life oozes out of it.

Similarly Mutations II is even sterner. It's hard to tell - even after repeated listenings - whether Shapey has any peace in mind. Or whether - perhaps like Shostakovich - he really does despair and simply wants to portray incoherence without limit. Not that the music lacks direction. Again, that's a strength of Holzman's. It moves towards and away from centres of gravity tonally. Yet Mutations II does seem to be coming apart in all other respects.

Nowhere is Holzman's identification with the way Shapey was thinking when he conceived these pieces clearer, nor is Holzman's expert grasp of the music more stunningly visible, than towards the end of Mutations [tr.6] - and, for that matter, throughout the whirlwind Mutations II [tr.7]; those four hands again! Amazing.

21 Variations is much more figurative, chromatic, somewhat less abstract - at least in conception. The clusters, chords and clamour are as prominent as ever. Yet they are less the vehicles for the variations' development; more the result. Once again, Holzman is completely in tune with such an underlying purpose; he pulls out every nuance and subtlety without losing sight of Shapey's intention. In other words this is a performance where flourish, virtuosity (however tempting and even inevitable it could have been) is rejected for insight, patience and authority. Authority of a curious, not a demonstrative, kind.

Both Sessions and Shapey had few misgivings about distilling their reactions towards their century (and its art, its music) into abstract and almost romantically nostalgic styles. That, perhaps, is what they have most in common. Not that Holzman is out to build his performances entirely - or even chiefly - on commonalities. But what each composer's approach says about the other's is always illuminating from the hands of someone who is so at home in, and positive about, both. This makes this a special CD with few others exposing Shapey's music in particular to the same extent. It will not disappoint.

The presentation of this CD with an informative essay by Holzman and a reference to his lecture on Shapey is good; it's businesslike and a little severe - but a great background to two composers who surely deserve reassessment. Outstanding playing like Holzman's here is more than a giant leap towards that. His total understanding of the music, its context and its strengths commend it to us not for its perceived difficulty or lamentable obscurity, but its beauty and power."