As an artist and art theorist, Allan Kaprow (*1927 in Atlantic City / USA, †2006 in Encinitas / USA) worked on the development of improvised forms of action art, for which he coined the term “happening,” in 1958. He produced more than 250 happenings, including Time Pieces for the 1973 project ADA – Aktionen der Avantgarde, organized by the Neuer Berliner Kunstverein with the Artists’ Program of the Deutscher Akademischer Austauschdienst (DAAD) and the Berliner Festspiele. Drawing on the influence of conceptual art, ADA initiated performances, actions, and happenings in public space in West Berlin over a period of several days.