As a longtime fan of children's literature and series books, I've always been fascinated by the 'Magic Tree House' series by Mary Pope Osborne. The series has been a staple for young readers since the first book, 'Dinosaurs Before Dark,' was published in 1992. Over the years, Osborne has expanded the universe with a mix of adventure, history, and fantasy, captivating generations of kids.
As of now, there are 68 main series books, divided into two arcs: the original 28 books, which are shorter and more focused on introducing historical and scientific concepts, and the 'Merlin Missions,' which are longer and delve deeper into fantasy elements. Additionally, there are over 30 supplementary 'Fact Tracker' nonfiction books that provide educational content related to the topics explored in the main series. The sheer volume of books ensures that there’s always something new for curious young minds to discover.