"Magic Tree House: Adventures with Jack and Annie" is a popular children's book series written by Mary Pope Osborne. The series follows two siblings, Jack and Annie, who discover a magical tree house filled with books. Each book transports them to different times and places, allowing them to experience exciting adventures and learn about history, science, and culture. Throughout their journeys, Jack and Annie encounter various characters and challenges that help them grow and develop problem-solving skills. The series combines elements of fantasy and education, making it a favorite among young readers and educators alike.