Kewpie dolls are based on illustrations by Rose O'Neill that appeared in Ladies' Home Journal in 1909. These illustrations,which incorporated words and pictures with the recurring Kewpie characters, are considered to be early versions of the comic strip medium. The small dolls were extremely popular in the early 1900s. They were first made out of bisque and then celluloid. In 1949, Effanbee created the first hard plastic versions.
Their name, often shortened to "Kewpies", in fact is derived from "cupid", the Roman god. The early dolls, especially signed or bisque, are highly collectible and worth thousands of dollars. The time capsule at the 1939 New York World's Fair contained a Kewpie doll. The term "Kewpie doll" is sometimes mistakenly applied to the troll doll.
Many other articles were made using their images, like coloring and poem books, cups, plates, curios, etc. The incredible success of these characters made their creator rich and famous. It's a rare example of a woman becoming successful in the media business at such an early date. Kewpies should not be confused with the baby-like Billiken figures that debuted in 1908.
What's it worth? Take a look at this Kewpie price guide: sold listings for a value indication.