A type of abstract art, particularly sculpture, characterized by extreme simplicity of form and a deliberate lack of expressive content; it emerged as a trend in the 1950s and flourished particularly in the 1960s and 1970s. The roots of Minimal art can be traced to the geometrical abstractions of Malevich and the ready-mades of Duchamp in the second decade of the 20th century, but as a movement it developed mainly in the USA and its impersonality is seen as a reaction against the emotiveness of Abstract Expressionism. According to The Tate Gallery: An Illustrated Companion (1979), ‘The theory of minimalism is that without the diverting presence of “composition”, and by the use of plain, often industrial, materials arranged in geometrical or highly simplified configurations we may experience all the more strongly the pure qualities of colour, form, space and materials.’ Minimal art has close links with Conceptual art (Minimalist sculpture often has a strong element of theoretical demonstration about it, with the artist leaving the fabrication of his designs to industrial specialists), and sometimes there are affinities with other contemporaneous movements, such as Land art. There is even a kinship with Pop art in a shared preference for slick, impersonal surfaces (some Minimal artists, however, have used ‘natural’ materials such as logs rather than machine-finished products). The leading Minimalist sculptors include Carl Andre, Don Judd, and Tony Smith. Minimalist painters (for whom the immediate precedents were Albers and Reinhardt) include Frank Stella (in his early work) and Hard-Edge abstractionists such as Ellsworth Kelly and Kenneth Noland.