Carolyn Keene is the pseudonym of the author(s) of the Nancy Drew mystery stories and The Dana Girls mystery stories, both produced by the Stratemeyer Syndicate.
First published in 1930, Mildred Wirt Benson and Harriet Adams (Stratemeyer’s daughter) are often credited as the primary writers of Nancy Drew books. They were initially paid $125 for each book and were required by their contract to give up all rights to the work and to maintain confidentiality. Other ghostwriters included James Duncan Lawrence, Walter Karig, Nancy Axelrad, Priscilla Doll, Charles Strong, Alma Sasse, Wilhelmina Rankin, George Waller Jr., Margaret Scherf, and Susan Wittig Albert.
Also involved in the Nancy Drew writing process were Harriet Stratemeyer Adams’s daughters, who gave input on the series and sometimes helped to choose book titles; the Syndicate’s secretary, Harriet Otis Smith, who invented the characters of Nancy’s friends Bess and George; and the editors at publishers Grosset and Dunlap. The editors at Grosset and Dunlap were so heavily involved in writing the Drew books that they won the rights to the first 56 titles as the result of a 1980 lawsuit.
In 1986, the Syndicate was bought by publishers Simon & Schuster; the Drew books are now handled by Mega-Books, a New York book packager.
Source: Wikipedia