Abstract Expressionism: A movement characterized by personally expressive imagery and brushwork and an attitude of freedom from traditional social and aesthetic values. Among the major luminaries of the 1940s and '50s era were William Baziotes, Arshile Gorky, Franz Kline, Hans Hofmann, Willem de Kooning, Jackson Pollock, and Clyfford Still. American Regionalism: At its height during the Depression (1930s), this movement emphasized rural American values. Artists such as Thomas Hart Benton, John Steuart Curry, and Grant Wood painted in a realistic manner - a pointed contrast to the Abstraction and Cubism of European (and European-influenced American) artists - subjects that recalled a Jeffersonian vision of America.
Color-Field painting: An offshoot of Abstract Expressionism, this style of painting concerns itself less with the gestural (expressive) quality of brushwork or forms than the atmospheric effects of large areas of color that encompass an entire canvas. Helen Frankenthaler, Barnett Newman, Morris Louis, Kenneth Noland, and Jules Olitski are among the most notable Color-Field artists.
DADA: An art based, as its meaningless name would suggest, on anti-rationality and anti-high culture. The high priest of DADA, Marcel Duchamp, drew a mustache on a reproduction of the Mona Lisa and exhibited bicycle tires and urinals.
German Expressionism: An art, largely represented in paintings and graphic prints, of scenes of madness and paranoia, that reflected post-World War I German sensibilities of a world gone wrong.
Formalism: An approach to works of art that emphasizes the purely ``art'' qualities - such as line, composition, color, and plastic form - while eschewing such concerns as subject matter or the historical time period in which the piece was created. As one of formalism's greatest proponents, Albert Barnes wrote in his 1925 study, ``The Art of Painting,'' ``the form which gives the essence of the thing, makes it what it is.''
Pop Art: A reaction to the heated, gestural quality of the Abstract Expressionists and the nonrepresentational imagery of the Color-Field painters, Pop Art arose in Britain and the United States as an ironic celebration of mass media, advertising, and popular culture. Jasper Johns, Roy Lichtenstein, Robert Rauschenberg, James Rosenquist, Andy Warhol, and Tom Wesselman are some of the leaders of this movement.
Surrealism: Similar to both DADA and German expressionism, this was an art form that followed the First World War, representing a desire by (mostly French) artists to recreate the world, not along the lines of rationalism that had led Europe to a destructive war, but on the basis of free association and the creativity of the unconscious mind. Surrealists were influenced by the writings of Sigmund Freud.