The Bobbsey Twins was the longest-running series of books for children. The books told the adventures of four siblings, who were two sets of twins. The older pair, Nan and Bert, were tall and lean, with dark hair and eyes. They started out around age 8, and grew to age 12. The younger ones were Freddie and Flossie. These two were plump, with blonde hair and blue eyes. They started as 4-year-olds, but settled at age 6. They lived with their parents (a lumber merchant and homemaker) and two black servants in a Northeastern suburb called Lakeport. The stories were fun and innocent, targeted at young readers of both sexes.
The first Bobbsey Twin book was written in 1904 by Edward Stratemeyer (who also created Nancy Drew and The Hardy Boys, among others) under the pseudonym Laura Lee Hope. Stratemeyer then hired ghostwriters to continue the series, usually from his own outlines or title suggestions. 72 books were published between 1904 and 1979, when Stratemeyer's company, Stratemeyer Syndicate, was sold to Simon and Schuster. The publisher started publishing a new Bobbsey Twins series with more modern characters and plots. In 1987 it was revamped again, and this version was published until 1992, when the Bobbsey Twins were finally discontinued after 88 years and 116 books.