Dan Flavin belonged to a generation of artists that redefined American sculpture in the wake of the Abstract Expressionists, who had redefined American painting. His contemporaries included Lee Bontecou, John Chamberlain, Robert Irwin and Donald Judd, all of whom were inspired by the large scale, saturated colors and simple compositions of the Abstract Expressionists. With them, Mr. Flavin moved sculpture away from an implicitly figurative, usually Cubist vocabulary toward a new focus on space itself, often defined by daringly impersonal use of new industrial materials. The material Mr. Flavin fastened on, the fluorescent light fixture in its many colors and lengths, was at once sensuous and austere, straightforward and celebratory. Flavin once wrote that ”the actual space of a room could be disrupted and played with by careful, thorough composition of the illuminating equipment.” And as the critic John Russell enthused: “The fluorescent light has a soft enveloping glow, quite unlike the needly, pinched aggressive quality of neon . . . but there is no sentimentality, either. Flavin uses candy colors, but he leaves out the sugar substitute. The pieces have no corporeal substance. Switched off, they are as inert as a broken phonograph. Switched on, they lead a charmed life, doubling back and forth between dream and reality.”