The document provides an overview of Art Nouveau, an international style of decoration and architecture from the late 19th to early 20th century characterized by flowing, sinuous lines depicting leaves and flowers. It discusses key features of Art Nouveau including organic and dynamic forms, curved designs, and avoidance of historical traits. Notable Art Nouveau practitioners and their works are mentioned for Britain, France, Spain, Vienna, and the US. Two examples of Art Nouveau architecture, Casa Mila in Barcelona and Hotel Guimard in Paris, are described in more detail to illustrate the dominant curved lines and arches as well as root-like designs.