Magic Tree House is an American series of children's books written by the American author Mary Pope Osborne. The original American series was illustrated by Salvatore Murdocca until 2016, after which AG Ford took over. Other illustrators have been used for foreign-language editions.
The series consists of two groups. The first group consists of books 1–28, in which Morgan Le Fay sends Jack and Annie Smith, two normal children who are siblings from the fictional small town of Frog Creek, Pennsylvania, on numerous adventures and missions with a magical tree house. The second group, referred to as the Magic Tree House: Merlin Missions, begins with book 29, Christmas in Camelot. In Merlin Missions, Jack and Annie are given quests by the ancient wizard Merlin the Magician. These books are longer than the previous 28, and some take place in fantasy realms like Camelot. Kathleen and Teddy are two apprentices who befriend Jack and Annie during their adventures, with one of these adventures being to free Kathleen from a spell. The two occasionally join Jack and Annie, and, when they don't, provide them support instead. During Super Edition #1, Teddy sends them on a mission instead of Morgan or Merlin. The companion Magic Tree House Fact Trackers are co-written by Mary Pope Osborne with her husband Will Osborne or her sister Natalie Pope Boyce.
In the beginning, Mary Pope Osborne wrote the books with Morgan sending the children on missions. Then she switched over to them being sent on missions by Merlin. About 10 years later, in 2014, she switched back to writing only the books with Morgan sending them on missions. These books were, again, much shorter. In addition to the books listed below, Mary Pope Osborne appears to still be writing the series, having released "#37 Rhinos at Recess" in 2023.