Repons may well be Boulez' crowning achievement, a spatial performance enhanced with digital accompaniment/effects. Barbara Jepson has a fascinating article describing the technological demands of a performance in her Wall Street Journal column. Repons, a "work in progress," has been modified over the years, now over twice the duration of the original score, with updated technological instruction. Universal Edition now presents an oversize score (11 3/4" x 16 1/2") of its current iteration.