Around the turn of the century design was emerging from 19th century revivalism. Designers were turning their back on the influence of the past. They were searching for new sources of imagery, and they turned to nature and to abstraction. They developed a style based on swirling, sinuous forms derived from nature but highly stylised. A lot of the imagery was drawn from insects, peacocks and so on. There was a strong element of eroticism and the exotic. There was very little influence from the past. Art Nouveau was a modern style that looked towards the future, so it came to be known as "new art."
Arthur Mackmurdo is generally considered to be the inventor of Art Nouveau. He was a British designer from the Arts and Crafts tradition. This is the title page of a book on the churches of Christopher Wren (1883) [Fig. 1]. It was a wood cut. It has vivid flowing forms derived from nature but exaggerated. It has elongated birds in the margin - the forms have been distorted to make them fit into the overall decorative scheme. Mackmurdo invented the "whiplash curve" which is the hallmark of Art Nouveau design.

Fig. 1 Wren's City Churches by Arthur Mackmurdo
His furniture designs are similar. This is the Thistle chair, which he designed in 1883 [Fig. 2]. It has the same flowing lines almost like calligraphy, but here they are realised in three-dimensional form. It was fluid, asymmetrical, almost plastic. This was the basis of the Art Nouveau style.

Fig. 2 Thistle Chair by Arthur Mackmurdo
Art Nouveau took its name from a gallery called L' Art Nouveau which was opened in Paris by Siegfried Bing, who is usually called Samuel Bing. The style lasted from 1895 to 1905. Whereas Arts and Crafts had expressed the nature of the materials, Art Nouveau was almost a denial of them. It was as if they saw it as a challenge to overcome the limitations of the materials with artistry.
One the most visible manifestations of Art Nouveau were the cast iron railings of the Paris metro-system [Fig. 3]. These are all over Paris. These were designed by Hector Guimard. They were inspired by nature, but they have been conjured into swirling lines, almost like living tendrils. The lamps emerge like drooping flower buds. There's a sense of movement having been frozen in space, which creates a strange tension. Guimard was influenced by the asymmetry of Japanese design. This is still within the limitations of cast iron.

Fig. 3 Paris Metro Station by Hector Guimard
You see the same treatment applied to wood and even stone. This is an Art Nouveau doorway in Paris that has been sculpted to give this elaborate, almost plastic form [Fig. 4]. This seems to deny the basic rigidity of wood and stone. This is a long way from truth-to-materials.

Fig. 4 Art Nouveau doorway in Paris
Art Nouveau was a style that affected every form of design. René Lalique was a jewellery designer. His imagery was based on female forms and insects [Fig. 5]. There is a fascination with distortion. Here you have an anthropomorphic distortion - a female figure with insect wings. Lalique's work was immaculately crafted. There was no sense of how it had been made; it's meant to be received as a completed work of art.

Fig. 5 Lalique jewellery
A leading glass maker was Louis Comfort Tiffany, who was born in New York but studied in Paris. He had been part of the Art Nouveau phenomenon since the beginning because he exhibited at the L' Art Nouveau shop from 1895. He tended to work with stained glass, which allowed him to achieve iridescent effects and vivid colours.
Here are three pieces by Tiffany [Fig. 6]. The one in the centre has a metal stand shaped like a plant stem and rose petals on the shade. It has a sinuous, drooping form. The one on the left has a more plastic treatment of the glass. It features bizarre insect life in the form of dragon flies. The last one uses the image of a spider web, which is another reference to sinister insect forms. All three are well-crafted and jewel-like.

Fig. 6 Tiffany lamps
A lot of Art Nouveau designs look somehow unreal. This was the period when Sigmund Freud was developing his theories about the human mind and sexuality. In art and literature there was a movement called Symbolism. Art Nouveau was creating a fantasy world, a sensuous, mystical dream world. The separate arts of architecture, furniture, sculpture dissolved into one overpowering, sensuous mass. For that reason it really helped to establish interior design as a valid practice, and within Art Nouveau you see some of the first consciously designed interiors.
One of the best architects was Victor Horta (1861-1947), from Belgium. He was an architect, but he was particularly skilled in decorative iron work. He designed the interiors for the Hotel Tassel in Brussels (1892-3). This is the entrance hall and staircase with exuberant Art Nouveau railings [Fig. 7]. They are similar to Guimard's metro stations. This is another unified scheme where Art Nouveau permeates every aspect. In Horta's work the underlying form seems to dissolve - it is overtaken by swirling linear patterns. Again, there's no real historical influence on his work; it's pure abstraction.

Fig. 7 Hotel Tassel by Victor Horta