The Art Nouveau movement was ushered in during the 1890's and is generally considered defunct by about 1910. The movement which started in France was not confined to that country, and there were practitioners of the style from the United States, Belgium, Italy and elsewhere. The movement was started by Eugene Grasset, a Swiss artist (1845-1917) who arrived in Paris in 1871. As he can be considered the father of Art Nouveau, the epitomy of the movement was most asuredly Alphonse Mucha, a Czech (1860-1939) who arrived in Paris in 1887. Some other well known illustrators of the style were Paul Berthon (1872-1909), who was a student of Grasset, Pierre Bonnard (1867-1947), Louis Rhead (1857-1927) American, Privat Livemont (1861-1936) Belgian, Henry Munier (1869-1942) Belgian, Will Bradley (1868-1962) American, and others.
Many more well known artists of this period, especially from France, are considered part of the Art Nouveau movement. Although this is a consideration due more to their artwork being contemporary to the Art Nouveau period rather than it is that their art was truely indicative of the style. Artists like Jules Cheret (1836-1932) practiced a style called "La Belle Epoque". He was very prolific in producing both posters and periodical illustrations, which are highly sought after.
Other big names from this period are Toulouse-Lautrec, Steinlen, Orazi, Vuillard, Cappiello, Pal, and Penfield to name a few. Also, many wonderful posters and illustrations were created by anonymous artists, so don't let the lack of a signature or monogram stop you from purchasing a piece of illustration art that you like.
The artists of the Art Nouveau style were more illustrators than they were painters. These artists were involved with posters and periodical illustrations. As such, their art is more available to collectors than that of the artist that used strictly oil or watercolor. In some cases, a lithographic illustration from this period may have been produced in the 5,000 to 10,000 piece range, whereas in other cases, maybe only a few hundred of a particular lithograph were produced. Today, as the lithographic posters from this period are going for prices which are far out of the reach of most collectors, the smaller illustrations are becoming popular and sought after, and may in many cases be scarcer than most poster illustrations. In fact, many of these artists did most of their work for periodicals and created some of their best work for magazine covers and advertisements. Many of these are rare today and underpriced in the marketplace, making them an excellent investment.