Season 4 reveals the inspiration, vision and techniques behind the creative works of 17 contemporary artists. Art21 travels across the country and abroad to film painters, sculptors, photographers, and filmmakers in their own spaces and in their own words. Viewers are invited behind-the-scenes to see artists at work in their studios, homes, communities, and in sites as diverse as an old-growth forest near Seattle, a military base in California, a theater academy in Warsaw, and a film set, in addition to galleries and museums. The artists profiled speak directly to the audience, describing their passions, impulses and methods.

Included in the season are artists Robert Adams, Allora & Calzadilla, Mark Bradford, Mark Dion, Jenny Holzer, Pierre Huyghe, Alfredo Jaar, An-My Lê, Iñigo Manglano-Ovalle, Judy Pfaff, Lari Pittman, Robert Ryman, Laurie Simmons, Nancy Spero, Catherine Sullivan, and Ursula von Rydingsvard.

Major underwriting for Season 4 of Art in the Twenty-First Century is provided by National Endowment for the Arts, PBS, Agnes Gund and Daniel Shapiro, Nathan Cummings Foundation, Bloomberg, The Andy Warhol Foundation for the Visual Arts, The Horace W. Goldsmith Foundation, Bagley Wright Fund, and W.L.S. Spencer Foundation.

Season 4 premiered in October 2007 on PBS.