Robert Irwin began his career as a painter. In the late 1950s he joined the Ferus group, a daring bunch of young avant-garde artists in Southern California. Irwin, influenced by the group, created abstract expressionist paintings until he realized that the “emotion” that had inspired his work was usually irrelevant six months later. He began to reduce his art to pure optical sensation, creating compositions of fields of colored dots and horizontal lines in his so-called pick-up-sticks paintings. In the late 1960s, Irwin moved away from painting and began using unobtrusive materials such as glass, scrim, tape, and lighting to change the feel of a room and to heighten the viewer’s awareness of space. Since the late 1970s, Irwin has focused on outdoor spaces but continues to use light to call attention to the act of perception.