An art form made popular in the mid 1960s through the 1970s, it has been described as a "document of the artist's thinking". The term became an all-embracing term for art forms that fit neither the description of painting nor sculpture and included Performance Art, Video Art and Earth Art. The theory is that art exists for its own sake. Known also as Idea Art, it came to widespread public awareness through the 1967 summer issue of "Artforum", in an article by Sol LeWitt. However, artists Henry Flint and Edward Kienholz had written earlier about Conceptual Art, which was a reaction against the impersonality of Minimalism and the commercialism of Pop Art. Joseph Kosuth in a 1969 essay also wrote what has been described as a "founding text of Conceptualism". (Princenthal). In that writing, he asserted that philosophy was dead and was replaced by art based on thought and material aspects that were disposable. Conceptual artists include Kosuth, Marina Abramovic, Adrian Piper, John Baldessari, Mel Bochner, James Lee Byars, Dan Graham, On Kawara, Yoko Ono, Bruce Nauman, Dennis Oppenheim and Richard Tuttle. Sources: Robert Atkins, "ArtSpeak"; Nancy Princenthal, 'Reading Between the Lines', "Art in America", March 2005.