Keith Sonnier (1941–2020) was a pioneering figure of postminimalist sculpture whose innovative use of neon and industrial materials transformed the language of contemporary art. Born in Mamou, Louisiana and trained at Rutgers University, Sonnier emerged in the late 1960s as part of a generation redefining sculpture through process, color, and unconventional materials. His breakthrough neon works introduced light as a sculptural medium, creating luminous drawings in space that engaged architecture, perception, and sensory experience. Sonnier’s work has been exhibited internationally, including major solo shows at the Whitney Museum, MoMA PS1, and the New Museum, and is represented in the permanent collections of MoMA, the Guggenheim, Centre Pompidou, and LACMA. His practice bridged technological innovation with intuitive gesture, establishing him as one of the most influential sculptors of his era.