From the 1950s to the early 1980s, Harry Shunk and János Kender photographed the incredible effervescence of the artistic avant-garde in Paris and New York. The first monograph dedicated to this remarkable photographic archive through over 800 photographs, several illustrated essays counting the remarkable history of this body of work composed of over 200 000 vintages, contact prints as well as negatives. Shunk-Kender had mixed with artists such as John Baldessari, Joseph Beuys, Dan Graham, Yayoi Kusama, Roy Lichtenstein, Claes Oldenburg, Robert Rauschenberg, Jean Tinguely, Jacques Villeglé, Andy Warhol ... Their photographs bear witness to the emergence of new creative acts, from the everyday life of the studios, the public performances, the world of the galleries, and the milestone openings of groundbreaking exhibitions. At once major documents on the international avant-gardes of the 1950s to 1970s, these eyewitness images also established specific photographic systems and devices. They captured faces, creative gestures, the life of the studio, evenings between artists and collectors, using framings and approaches that constitute photographic oeuvres in their own right.