Magic Tree House is a book series for young children by Mary Pope Osborne. The series features two children, the bookworm Jack and his adventurous and imaginative younger sister Annie, who travel to historical places using a magic tree house. The magic tree house belongs to Morgan Le Fay who, in the series, is King Arthur's sister and a librarian. She uses the magic tree house to gather books from time and space.

Mary Pope Osborne grew up in the military, and by the time she was fifteen had lived in Oklahoma, Austria, Florida and four different army posts in Virginia and North Carolina. After graduating from the University of North Carolina at Chapel Hill in the early 1970's, Mary traveled all over Europe, and spent the first six weeks of her trip living in a cave on the island of Crete. She then joined up with a group of European young people and traveled in rickety vans through sixteen Asian countries, including Iraq, Iran, Afghanistan, Pakistan, India and Nepal. She was a bartender, an acting teacher, a waitress, a travel agent, a window dresser, and a medical assistant — all before becoming an author! Now she is the author of many highly acclaimed picture books, early chapter books, middle-grade biographies, and young adult novels. In February 1993, Mary was elected the 27th president of the Author's Guild, the oldest, most established organization for writers in the United States.