Robert Mangold (b. October 12, 1937, North Tonawanda, New York) builds paintings from circles, arches, and polygons that are deliberately incomplete: divided across multiple panels, cropped at the canvas edge, or interrupted mid-curve, so that a viewer's mind has to complete the geometric form the eye cannot fully see, turning perception itself into the subject rather than the shape.

Mangold trained at the Cleveland Institute of Art, then earned his BFA and MFA from Yale, where his classmates included Richard Serra and Brice Marden. After graduating he worked as a guard at the Museum of Modern Art alongside fellow future Minimalists Sol LeWitt and Robert Ryman. His first solo exhibition, Walls and Areas, opened at Fischbach Gallery in 1964, large paintings on Masonite and plywood related to the architecture of lower Manhattan in solid form and atmosphere; his work appeared two years later in the epoch-defining exhibition Primary Structures.