A pioneer in the medium of video art, Bill Viola's work explores the spiritual and perceptual side of human experience. Since 1970 he has created videotapes, architectural video installations, sound environments, electronic music performances and pieces for television. Works include Hatsu Yume (First Dream), The Passing, and installations Room for St. John of the Cross, The Messenger and The Quintet of the Astonished, recently shown at the National Gallery, London in "Encounters, New Art ...