PLEASE SEE PHOTOS. MISSING BOOK #20. The Mary Pope Osborne Magic Tree House Series Box Set Books Illustrated is a collection of 28 novels in the Magic Tree House series by Mary Pope Osborne. These adventure-filled books are aimed at children and young adults, with a focus on topics such as fantasy, magic, and action. Each book in the set is illustrated, making them engaging and visually appealing for young readers. Perfect for fans of the series or those looking to explore new fictional worlds, this box set offers a captivating reading experience.