Maybe it's the relatively unusual instrumentation of this quartet (trumpet/fluegelhorn, two acoustic basses and drums), and more likely the talents of the individuals involved, but among many other delights, the sense of air-filled space, of the listener being among the musicians, is astonishing.

Bill Dixon's horns flit and hover in the air above, describing arabesques as intuitive as they are mathematical, as natural and arcane as bird cries.

The dual basses of Barry Guy and William Parker, with approaches so different in manner that they often sound as though issuing from unrelated instrument, prod and cajole from the sides, sometimes echoing Dixon, other times steering the direction of the improvisation as they see fit, and always rambunctiously inventive.

Tony Oxley's percussion, as unobtrusive and essential as a floor, pervades the atmosphere, providing sonic surfaces for the others to glance off or to mirror.

Graham Lock's fine liner notes assure readers that Dixon provided a compositional framework for the group (who hadn't worked together as a quartet before this session), but it's a testimony to his conception that the entire recording has the aura of a superb, intimate, and powerful improvisation.

Paradoxically, if one concentrates on each individual's playing, there is a kind of sparseness, even hermeticism in the sound, but in the group context it becomes a lush, breathing, blooming creation.

In some ways, Vade Mecum II is an extension and descendent of Cecil Taylor's '60s classic Conquistador!, on which Dixon also played.

It is, in any case, one of the very finest jazz albums of the '90s and one that cannot be recommended too highly.