Melanie Rehak is the author of “Girl Sleuth: Nancy Drew and the Women Who Created Her.” Nancy Drew just turned 75 and still wields immense influence on the women who grew up reading her. They include Sandra Day O’Connor, Beverly Sills and Anne Strainchamps who talks with Melanie Rehak about how the character developed under various ghost-writers, and why girls love her so. We also hear an excerpt from the Laura Linney Listening Library production of “The Secret of the Old Clock.”