56 Nancy Drew Mystery Stories series

The Nancy Drew Mystery Stories was the long-running "main" Nancy Drew series, published between 1930 and 2003. Initially, titles were published by Grosset & Dunlap, but with #57 (1979) publication switched to Simon & Schuster. Some people consider these first 56 to be the original series and consider the Simon & Schuster series to be an entirely different series. The first 56 are considered to be the "classic" Nancy Drew books. In 2003, the series was discontinued, and a new, more contemporary series (Nancy Drew Girl Detective) was created in its place.