The Surrealist movement is a 20th-century phenomenon emphasizing the portrayal of subconscious rather than conscious images. Heavily influenced by both the Dada movement and the psychological research of Sigmund Freud, its art often takes the form of dream-like scenes, most famously in the bizarre scenes of Salvador Dalí (though as an aside Dalí himself was a bit of an outsider amongst Surrealists of his day, his right-wing politics clashing with the left-wing politics then favored in intellectual and artistic circles). The distaste for "normal" representational art it inherited from Dadaism, but in place of Dadaism's denial of meaning in art, Surrealism claimed art should have a meaning, but only to the subconscious mind (the influence of Freud's theories on the subconscious and its relation to the conscious mind is clear here).
The beginning of the movement is usually traced to the poet and Dada artist André Breton's 1924 Surrealist Manifesto, and quickly became a significant force in European art (a much more concise version of the Manifesto, written in 1925 and signed by many of the major artists of the movement, excellently captures its goals and spirit). In fact it became so dominant by its height that a large portion of the well-known names in 20th-century art can be considered Surrealists -- Max Ernst, Joan Miró, Salvador Dalí, Marc Chagall, Marcel Duchamps, and of course René Magritte himself.
Magritte's work shares the same aims as that of the other Surrealists, but differs markedly in its reliance on everyday ("real") objects rather than fanciful dream-like subject matter. Instead Magritte creates an almost jarring sense of surrealism in his works by portraying these entirely ordinary objects in ways they would never actually appear (as in the juxtaposition of the otherwise-ordinary night and day scenes in The Empire of Lights).
The important function of light in this painting is another common element of Magritte's works, and for this reason it's difficult to capture their essence with reproductions (either in books or online) -- the image linked to in the introduction has its contrast reduced so as to allow details to be visible in both the light and dark portions of the painting; another image preserves the striking contrast but loses the details of the dark portions of the painting in a mass of black. Thus one really needs to view the original painting to appreciate the full contrasts of light and color the way Magritte intended them to be seen. Fortunately, he actually painted several versions of this work (differing in details but with the same general style); some are in private collections, but enough are in museums that viewing the painting in person should be possible for many Americans and Europeans. Museums displaying versions of the work include the Guggenheim Musem and the Museum of Modern Art in New York City and the Museées Royaux des Beaux-Arts de Belgique in Brussels, Belgium.
This is the second in a series of articles focusing on individual works of art and their historical and artistic contexts. See also the first installment if you missed it.