The Bobbsey Twins in Tulip Land (The Bobbsey Twins, No. 42)

viii, 210 pp. Book 42 of the Bobbsey Twins series. "The Bobbsey Twins are the principal characters of what was, for many years,[quantify] the Stratemeyer Syndicate's longest-running series of American children's novels, penned under the pseudonym Laura Lee Hope. The first of 72 books was 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 twelve years old, and Flossie and Freddie, who were six."--Wikipedia