Reissner, Stellmacher and Kessel (R.S.K.) (est'd 1892)
Bohemian ceramics firm; main contribution to Art Nouveau was the "Amphora" range. (see here)

Ricketts, Charles de Sousy (1866-1931)
English sculptor whose Art Nouveau style was inspired by the work of the Frenchman, Rodin. (see here)

Rode, Godfred (1862-1937)
Danish ceramic decorator at Royal Copenhagen. Famous for underglaze seascapes.

Rohlfs, Charles (1853-1936)
American actor, stove maker and designer of furniture, particularly in oak (see here). Mark: burned initials.

Rookwood (1880-1960)
Foremost American producer of fine Art Nouveau pottery. (see here)

Rörstrand (est'd 1726)
Prominent Swedish pottery: producer of bold designs under the influence of French Art Nouveau. (see here)

Rosenthal, Philip (d.1937)
German potter and founder of the Rosenthal factory, producer of high-quality tablewares. Marks; printed.

Roseville Company (1890-mid-1940s)
American pottery established on the site of J.B.Owens' pottery; produced wares similar to Rookwood's Standard glazed wares. (see here)

Royal Copenhagen (1775-present)
Danish ceramics factory. Arnold Krog introduced innovative glazing and decorative techniques. (see here)

Royal Dux (1860-mid-20thC)
Bohemian ceramic producer known for classically-inspired figures.

Roycrofters, The (1895-1938)
American craft community founded by Elbert Hubbard (1856-1917) to produce simple furniture in the Mission style, textiles and metalwork. (see here)

Rozenburg (1883-1916)
Pottery whose "eggshell" porcelain is considered foremost Dutch contribution to Art Nouveau. (see here)

Sèvres (1750-present)
Renowned French ceramics factory, whose Art Nouveau pieces are acknowledged as the finest of the period. (see here)

Solon, Leon V. (1872-1957)
English ceramic designer and director of Mintons, 1900-09. (see here)

Speneer, Edward Napier Hitchcock (1872-1938)
English metalwork designer and co-founder of the Artificers' Guild.

Steinlen, Theophile-Alexandre (1859-1923)
Swiss-born, naturalized French, artist and posterist whose work reflected his socialist principles and love of animals, particularly dogs and cats. (see here)

Steuben (1903-present)
New York-based glassworks founded by Howkes family and Frederick Carder. (see here)

Stevens & Williams (c.1830-present)
Glassmakers at Stourbridge in the English Midlands, best known for fine cameo wares. (see here)

Stickley brothers (1891-1910)
George and Albert, brothers of Gustav, made oak furniture in a style popularized by Gustav, but of inferior quality. (see here)

Stickley, Gustav (1847-1942)
American furniture designer; produced pieces with an Arts and Crafts feel, notably his range of "Craftsman furniture". (see here)

Stickley L. and J. G. (c.1900-present)
American furniture makers of interior versions of the designs of their brother, Gustav Stickley. (see here)

Taylor, Ernest A. Q874-1951)
Scottish painter and furniture designer. (see here)

Tiffany, Louis Comfort (1848-1933)
Founder of Louis C. Tiffany in the United States, which initially designed interiors but is now better known for glasswares, particularly lamps. (see here)

Toft, Albert (1862-1949)
English sculptor of bronze figural pieces, mainly of ethereal, cloaked female subjects. (see here)

Toulouse-Lautrec, Henri de (1864-1901)
Renowned French commercial artist and posterist; depicted the seedier theatres and nightclubs of Paris. (see here)

Unger Brothers (1872-c.1910)
American silversmiths and jewelers. Most wares designed by Emma Dickinson. (see here)

Van Briggle, Artus (1869-1904)
American potter and pottery decorator. Worked initially for Rookwood; founded the Van Briggle Pottery Co. in 1902.

Van de Hoef, Christian Johannes (1875-1933)
Dutch sculptor, medallist and ceramicist, the main designer at Amstelhoek. Mark: painted.

Van de Velde, Henri (1863-1957)
Belgian architect and designer; worked with Siegfried Bing and at Meissen. (see here)

Van Erp, Dirk (1860-1953)
Dutch-born metalworker. (see here)

Vever (1821-1982)
Leading French Art Nouveau retail and manufacturing jewelers. (see here)

Villeroy and Boch (1836-present)
German producer of stoneware art pottery.

Vineland Glass Manufacturing Company (dates unknown)
American glassmaking firm with strong ties with Quezal.

Wahliss, Ernst (1863-1930)
Bohemian potter influenced by Michael Powolny.

Walter, Alméric (1859-1942)
French Art Nouveau glass artist; worked primarily in pâte-de-verre.

Webb, Thomas & Son (1856-present)
Stourbridge-based glassworks whose Art Nouveau glass includes Burmese ware, cameo glass and overlay wares. (see here)

Weduwe N.S.A. Brantjes & Co. (1895-1904)
Dutch ceramics factory. (see here)

Whitefriars Glass Works (c.1680-present)
Influential London glasshouse bought by James Powell & Sons in 1833. (see here)

Wiener Werkstätte (Vienna Workshops) (1903-32)
Series of Austrian craft workshops founded by Kolomon Moser and Josef Hoffmann. (see here, here, here and here)

Wüttembergischer Metallwarenfabrik (W.M.F.) (1880-present)
Austrian metalwork foundry; made decorative and domestic metalwork. Marks: stamped.

Zijl, Lambertus (dates unknown)
Dutch sculptor and ceramicist employed by Amstelhoek.

Zsolnay (est'd 1862)
Hungarian ceramics firm; helped the development of Art Nouveau in eastern Europe. (see here)