"The Case of the Green Ghost" is a vintage paperback book from 1999, part of "The New Adventures of Mary-Kate & Ashley" series by author Carol Ellis. This mystery novel, intended for young adults, features the twins Mary-Kate and Ashley Olsen as they solve the case of the Green Ghost. With 84 pages, the book is written in English and is a great addition to the collection for fans of the 1990s era of juvenile literature.