In this volume, four distinct works by the important American sculptor Richard Serra are linked by a common theme: each is based on the relationship between the viewer and a horizontal or planar elevation on eye level. Elevations, Repetitions is a complex of 16 elements of different heights; Equal Weights and Measures is composed of six equal blocks of forged steel, rotated such that it's difficult to confirm that sameness. No Relief consists of two 60-foot, six-inch-thick horizontal slabs flush to the wall on opposite sides of a narrow room, compressing the elongated space. And Round is a forged steel work with a diameter of 84 inches and a weight of 50 tons, set on an unnerving slope. Serra's other recent projects include an eight-part permanent installation at the Guggenheim Museum, Bilbao and a Spring 2007 survey at The Museum of Modern Art.