Gerry Badger is a photo historian and critic. He regularly writes and lectures on photography and has curated a number of exhibitions. His published books include Collecting Photography and monographs on John Gossage and Stephen Shore, as well as Phaidons 55s on Chris Killip (2001) and Eugene Atget (2001). Mary Panzer is a historian with a special interest in American photography. She was Curator of Photographs at the National Portrait Gallery, Smithsonian Institution, in Washington, DC, from 1992 to 2000. Amanda Hopkinson is a writer, translator, curator and critic, whose area of speciality is Latin America. She is also International Literature Officer for the Arts Council of England and a Senior Research Fellow at Cardiff University. Sylvie Aubenas is Chief Curator of the 19th-century photographic collections at the Bibliotheque Nationale, Paris. She has curated several exhibitions on the work of such photographers as Nadar, Charles Aubry and Le Gray. Bonnie Yochelson is a former curator of prints and photographs at the Museum of the City of New York, where she supervised the cataloguing and printing of the Riis collections. She is completing an interdisciplinary study on Riis with support from the National Endowment for the Humanities.