Answer: Carolyn Keene

Between 1930 and the present, at least one (and sometimes multiple) Nancy Drew mysteries, books in various Nancy Drew spin-off series, and The Dana Girls series (1934-1979) were published every single year, barring a one year pause during 1958. With over 700 titles to her name over a period of 91 years, that would make Carolyn Keene one of the most prolific and longest active writers ever…if she existed in the first place.

Much like the equally popular Hardy Boys franchise of young adult detective fiction, Nancy Drew is not the work of a single author. Neither Frank Dixon (the author of The Hardy Boys) nor Carolyn Keene are real people, but simply names assigned to a cast of frequently changing ghostwriters. Over the years, the Nancy Drew franchise has employed a multitude of different authors as ghostwriters, including Mildred Wirt Benson, the first and most closely associated with the series.