Art: The Avant-Garde: Subtle, Cerebral, Elusive

FOR the past nine years, Robert Ryman, 38, a shy, quiet, Tennessee-born part-time art teacher, has lived in Manhattan lofts and tenements and painted "naked" pictures. That is to say, he covers rectangles of metal, canvas or paper with white paint and then, instead of framing them or stretching them, he mounts them as close to the wall as he can get them, sometimes stapling them directly to the plaster. The effect is unnerving. The wall seems to have developed a gaping hole.

Ryman's pictures are so unsettling, in fact, that some who see them...