There was back and forth between Ms. Greene and American Girl executives about how to handle certain situations, including the fact that in the first book Rebecca and her father work in his Rivington Street shoe shop on Saturdays, the Jewish Sabbath.

“There were full meetings about that,” said Ms. Dennis, who learned a lot about Judaism during the project. “There were so many different styles of Jewish practice, some stricter than others, in 1914 and today. What our research told us was the greater pressure during that time period was assimilation and blending in and becoming American.”

As Ms. Greene worked on the books, company designers set about figuring out what Rebecca should look like. The company’s research had found that Rebecca’s Russian-Jewish descent allowed a range of physical characteristics, creating a wide palette of choices, said Megan Boswell, the director of design and development. Facial structure is not typically an issue because the company generally chooses from an existing set of molds.

Hair color was a big issue, debated for years. At first it was a dark auburn, but it was thought that might be too untypical. Ms. Boswell said. Then dark brown, the most common hair color for Russian-Jewish immigrants, was discussed. But perhaps that would be too typical, too predictable, failing to show girls there is not one color that represents all Jewish immigrants.

“In the end, after many discussions weighing out the advantages of both approaches,” Ms. Boswell said, “we created what we felt was an optimum combination and gave her a new mid-tone brown hair color with russet highlights.”

This is not the first Jewish American Girl. The company has a series called “Girl of the Year,” which features contemporary characters, each available only for 12 months. The character for 2001 was Lindsey Bergman, and the opening of her only story book does not display the same misty affection for Jewish culture as do the Rebecca stories. Lindsey, as narrator, describes a matzo ball that is flung across a room: “If you don’t know what a matzo ball is, I’ll tell you,” she narrates. “It’s a slippery, dumpling-like blob of mush that floats around in chicken soup.”