During a career spanning half a century, Ileana Sonnabend helped shape the course of postwar art in Europe and America. Both a gallerist and a noted collector, Sonnabend promoted some of the most significant art movements of her time. Artists as varied as Vito Acconci, Mel Bochner, Gilbert & George, Jeff Koons, Jannis Kounellis, Mario Merz, Robert Morris, Claes Oldenburg, A. R. Penck, Robert Rauschenberg and Andy Warhol worked with Sonnabend, whose support for difficult avant-garde work was legendary. Published in conjunction with an exhibition that pays tribute to Sonnabend in honour of the Sonnabend family's gift of Robert Rauschenberg's well-known Combine Canyon (1959) to The Museum of Modern Art in 2012, Ileana Sonnabend: Ambassador for the New features approximately fifty works presented in Sonnabend's eponymous galleries in Paris and New York from 1962 through the late 1980s. A biographical essay by Leslie Camhi, artists' recollections of working with Sonnabend, and individual entries on the selected works provide further reflection on Sonnabend's taste and lasting influence.