The Hardy Boys: The Mark On The Door #27 by Franklin W Dixon is a vintage trade paperback book from the 1980s, part of the Hardy Boys series. This English-language novel, with illustrations, is intended for young adults ages 4-12 and belongs to the genre of juvenile fiction. The story follows the Hardy Boys as they solve a mystery involving a mark on the door, making it an engaging read for young readers interested in detective stories. With its nostalgic appeal and wholesome narrative, this book is a classic addition to any child's bookshelf.