Nocturnes, the term James McNeill Whistler applied to his nearly abstract moonlit landscapes, represent his signature contribution to nineteenth-century art. Inverting the plein-air principles of the French impressionists, Whistler created a series of works in which darkness, rather than light, structures the visual image. According to the artist’s mother, one particularly luminous summer evening in 1871 inspired Whistler’s first painting of London after dark. Over the course of the decade he produced more than thirty oil paintings with this theme. He subsequently expanded his exploration of urban darkness in London, Venice, and Amsterdam through the use of lithography, watercolor, and above all, etching to document and transform the texture of night.