One of the greatest dangers of altitude is sluggishness and the inability to summon up otherwise easily accessed memories. Nothing can be learned or retained at much above 9,000 feet, and the spontaneous retrieval system which is required for musicians to translate thousands of prompts into various motor actions is sorely lacking at any altitude. I have seen well-known musicians flounder on the stage at Aspen, to which they have just flown for a high-altitude concert, becoming reduced to infantile stabbings at the keys, their music bled of sophistication and subtlety and even notes by the invisible hand of atmosphere.

It is quite possible that, had I been lucky enough to have recorded these pieces at sea level, the performances might have been faster and more aggressive, although there seems to me to be a virtue in their easily absorbed flow, in their human rhythm, and the addition of performance clichés in a sea-level spasm of oxygenated exuberance might have led to juvenile excess, or to interpretations based on the fear of critics or audiences with expectations of imitative repetitions, of xeroxed CD sounds, or insecure mimings of ancient insights.