Suzanne Hudson is professor of art history and fine arts at the University of Southern California and cofounder of the Contemporary Art Think Tank and the Society of Contemporary Art Historians. She is the author of Robert Ryman: Used Paint, Agnes Martin: Night Sea, and Contemporary Painting, and coeditor of Contemporary Art: 1989–Present. Tanya Sheehan is the Ellerton M. and Edith K. Jetté Professor of Art at Colby College and Executive Editor of the Smithsonian Institution's Archives of American Art Journal. She is the author of Doctored: The Medicine of Photography in Nineteenth-Century America and Study in Black and White: Photography, Race, Humor, and editor of four volumes, including Photography and Migration.