Bobbsey twins

The Bobbsey Twins are the principal characters of what was, for many years, the Stratemeyer Syndicate's longest-running series of American children's novels, penned under the pseudonym Laura Lee Hope. The first of 72 books were published in 1904, the last in 1979, with a separate series of 30 books published from 1987 through 1992. The books related the adventures of the children of the upper-middle-class Bobbsey family, which included two sets of fraternal twins: Nan and Bert, who were 12 years old, and Flossie and Freddie, who were six.

Edward Stratemeyer himself is believed to have written the first volume in its original form in 1904. When the original series was brought to its conclusion in 1979, it had reached a total of 72 volumes. At least two attempts to restart the series were launched after this, but neither effort saw the popularity that the original series achieved.

Speculation that Stratemeyer also wrote the second and third volumes of the series is believed to be incorrect; these books are now attributed to Lilian Garis, wife of Howard Garis, who is credited with volumes 4–28 and 41. Elizabeth Ward is credited with volumes 29–35, while Harriet Stratemeyer Adams is credited with 36–38, 39 (with Camilla McClave), 40, 42, 43 (with Andrew Svenson), and 44–48. Volumes 49–52 are attributed to Andrew Svenson, while 53–59, and the 1960s rewrites of 1–4, 7, 11–13, and 17, are attributed to June Dunn. Grace Grote is regarded as the real author of 60–67 and the rewrites of 14 and 18–20, and Nancy Axelrad is credited with 68–72. Of the 1960s rewrites not already mentioned, volumes 5 and 16 are credited to Mary Donahoe, 6 and 25 to Patricia Doll, 8–10 and 15 to Bonnibel Weston, and 24 to Margery Howard.

In the original editions, the first books in the series (like those in previous Stratemeyer series) took place in a clear chronology, with the characters aging as time passed. The Bobbsey Twins: Merry Days Indoors and Out took place over the course of a school year, with Nan and Bert described as eight years old and Freddie and Flossie four. The second book, The Bobbsey Twins in the Country is set at the beginning of the following summer. The second part of the summer is chronicled in The Bobbsey Twins at the Seashore, which is written as a direct sequel to the previous book, tying up some plot threads. The fourth book, The Bobbsey Twins at School, begins the next autumn, with Nan and Bert "nearly nine years old" and Freddie and Flossie "almost five." Editors at the Stratemeyer Syndicate quickly realized that at this rate their young heroes would quickly age beyond their readership, and so the later books in the series (and in all revised editions) take place in a sort of chronological stasis, with the older twins perpetually 12 years old and the younger set 6.

...
Wikipedia