The Magic Tree House Book Set 1-31, with added 1-28, 163 page activities book. The added activities book is a comprehensive activity/study book. The 31 book set is a series based on the popular Magic Tree House books by Mary Pope Osborne. Published by Random House Children’s Books, these paperback books offer a fun and interactive learning experience for young readers. With engaging stories and educational activities, this study book set is a great way to encourage a love for reading while also promoting a variety of skills and knowledge.