Wolfgang Volz has worked with Christo and Jeanne-Claude as the exclusive photographer of their works since 1971. He was also project director (with Roland Specker) for Wrapped Reichstag and (with Josy Kraft) for Wrapped Trees, and was in charge of The Wall - 13,000 Oil Barrels, 1999. His close collaboration has resulted in many books and more than 300 exhibitions in museums and galleries around the world. Jacob Baal-Teshuva, born 1929, is author, critic and independent curator of museum shows. He studied at the Hebrew university in Jerusalem and the New York University. His numerous publications include works on Marc Chagall, Alexander Calder, Jean-Michel Basquiat, Andy Warhol and Christo and Jeanne-Claude. Jacob Baal-Teshuva lives and works in New York and Paris.