Ornament and Crime was an essay and a lecture by modernist architect Adolf Loos, that criticizes ornament in art, first given on 21 January 1908 in Vienna and first published in Cahiers d'aujourd'hui (issue 5 of 1913) under the German title Ornament und Verbrechen. It was under this challenging title that in 1913 the essay was translated into French; it was not published in German until 1929. "The evolution of culture marches with the elimination of ornament from useful objects", Loos proclaimed, linking the optimistic sense of the linear and upward progress of cultures with the contemporary vogue for applying evolution to cultural contexts. Loos' work was prompted by regulations Loos encountered when he designed a tailorshop without ornamentation next to a palace. He eventually conceded to requirements by adding a flowerpot.
The essay was written when Art Nouveau, which Loos had excoriated even at its height in 1900, was about to show a new way of modern art. The essay is important in articulating some moralizing views, inherited from the Arts and Crafts movement, which would be fundamental to the Bauhaus design studio and would help define the ideology of Modernism in architecture.
In Loos' essay, "passion for smooth and precious surfaces" he explains his philosophy, describing how ornamentation can have the effect of causing objects to go out of style and thus become obsolete. It struck him that it was a crime to waste the effort needed to add ornamentation, when the ornamentation would cause the object to soon go out of style. Loos introduced a sense of the "immorality" of ornament, describing it as "degenerate", its suppression as necessary for regulating modern society. He took as one of his examples the tattooing of the "Papuan" and the intense surface decorations of the objects about him—Loos says that, in the eyes of western culture, the Papuan has not evolved to the moral and civilized circumstances of modern man, who, should he tattoo himself, would either be considered a criminal or a degenerate.