Single sided handbill published in conjunction with the first performance of Allan Kaprow's first happening, "18 Happenings in Six Parts by Allan Kaprow," held October, 4, 6, 7, 8, 9, 10, 1959 at The Reuben Gallery, New York. Includes cast of participants: Kaprow, Rosalyn Montague, Shirley Prendergast, Lucas Samaras, Janet Weinberger, Robert Whitman, Sam Francis, Red Grooms, Dick Higgins, Lester Johnson, Alfred Leslie, Jay Milder, George Segal and Robert Thompson. Also includes "Instructions" describing, loosely, the actions of the happening. Developed within John Cage's experimental music class at The New School, "18 Happenings in Six Parts" has been described as the first "happening" in the lineage of works to be enacted by Kaprow's generation of artists, inclusive of Claes Oldenburg, Jim Dine, Robert Whitman and others.