Barry was one of the first to see that mass and volume in sculpture were not dependent upon visibility... But also, and perhaps more importantly, that language was a necessary component to communicate the idea in conceptual art.
Robert C. Morgan, cited in: Genocchio, Benjamin. "A Career Built on Exploring the Boundaries of Art", The New York Times, November 30, 2003
A Career Built on Exploring the Boundaries of Art - NYTimes.com