“Robert Overby: Works 1969–1987” provided an extraordinary opportunity to retrace the investigations into the usually unexpressed potentials of material in the work of this too-little-known artist. For Overby, who was born in 1935 and died in 1993, material was the site of all transformations; a partner to the artist, responding to his actions with its own; and—in the final analysis—a mystery, a harbinger of beauty. The exhibition, curated by Alessandro Rabottini in cooperation with the Centre d’Art Contemporain in Geneva (where the show opened), the Bergen Kunsthall in Norway (where