LORELAI: Honey, he did not plan an entire romantic evening complete with dinner and a junkyard, which we’ll get back to later, and then suddenly decide to dump you for no reason.
RORY: How do you know?
LORELAI: Because I have read every Nancy Drew mystery ever written. The one about the Amish country, twice. I know there’s more to the story than what you’re telling me.
Nancy Drew is a fictional girl detective who first appeared in the 1930 novel, The Secret of the Old Clock. She was created by publisher Edward Stratemeyer as a feminine version of the Hardy Boys mysteries he published, and the books are written by various ghostwriters under the name Carolyn Keene. For her independence and forthright nature, Nancy Drew is often seen as a positive role model for girls. Nancy Drew books are universally popular, and still being published.
The book that Lorelai refers to is The Witch Tree Symbol, first published in 1955, and the 33rd volume in the series. It is set in Pennsylvania Dutch country, and the Amish play an important part in the plot.