Simon & Halbig was an important German doll manufacturer that made heads for several different makers other than themselves.
Simon & Halbig (S & H) was founded in 1839, they began making dolls from 1869 to 1920 in their porcelain factories in Frafenhain and Hidburghausen, near Thüringia, Germany.
In 1920 they were bought by Kämmer & Reinhardt, who continued to produce dolls until 1932.
Simon & Halbig were known for there fine bisque doll heads and innovation in the doll industry, thus, they also supplied doll heads to many other well known doll manufacturers, that then attached to their own made body.
The American firm that used an S & H head are: Arranbee, the German firms that used a S & H head are: C.M. Bergman, Carl Berger, Cuno & Otto Dressel, Hamburger & Co., Heinrich Handwerck, Adolf Hülss (also spelled: Adolf HülB), Dr. Paul Hunaeus, Kammer & Reinhardt (did not have a porcelain factory, so all their heads were purchased from S & H), Louis Linder & Sohne, Franz Schmidt, Schoenau & Hoffmeister, Carl Trautmann, Welsch & Co., Schindel & Kallenberg Wiesenthal, Adolf Wislizenus and the French firms of: Fleischmann & Bloedel, Jumeau, Roullet & DeCamp and S.F.B.J.
What's it worth? Take a look at this Simon Halbig price guide: sold listings for a value indication.