Sol LeWitt was one of the most important minimal and conceptual artists. He was one of the founders of the radical, rationally-oriented aesthetic that was deployed as a reaction to the emotionally-oriented American Expressionism of the 1950s and 1960s. In Minimal Art, the form of the artworks is reduced to the extreme. Conceptual Art went one step further by making the concept or underlying idea of an artwork more important than its beauty or physical form. A major element of both movements is that the artist, as a maker of art, fades into the background.