Leon Golub's Paintings of Torturers.

Artist Robert Irwin. He's been a pivotal figure in American Art for over 30 years. He was one of the creators in the late 60s of the "light and space" movement, using unobtrusive objects, such as light, tape, and string to alter the viewers perception of the space in which the work is found. His work can be found in public spaces throughout the country, often using material natural to that environment, and delving into the "character" of the place.

Language commentator Geoff Nunberg recently visited the Language in Art Since 1960 exhibit at New York's Whitney Museum. He says the work he saw revealed how words in art can create dynamic social commentary in a way distinct from text on a page.

Works by the Swedish-born artist include an oversized rubber stamp in Cleveland, a clothespin in Philadelphia and a flashlight in Las Vegas. Oldenburg died July 18. Originally broadcast in 1992.