The 1959 Nancy Drew Mystery Stories book titled "The Hidden Staircase" by Carolyn Keene falls within the Mystery and Thriller genre and features the iconic character Nancy Drew. This book is part of the Nancy Drew series, which follows the adventures of a teenage detective as she solves mysteries and uncovers secrets. With a focus on suspense and intrigue, "The Hidden Staircase" is a classic addition to any collection of vintage Nancy Drew books.