Title: Magic Tree House
Content:  Magic Tree House is an American series of children's books written by the American author Mary Pope Osborne. The original American series is illustrated by Salvatore Murdocca, although 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 
Title: Magic Tree House
Content:  Magic Tree House: Merlin Missions books 1-27 were written for more advanced readers. They are more challenging adventures for readers ages 7–10. The Magic Tree House: Merlin Missions were originally ordered sequentially, starting at Book #29 (Christmas in Camelot). With the 25th anniversary re-prints, the books have been separated into their own distinct series and re-numbered starting at Merlin Mission #1.
Title: Magic Tree House
Content:  According to its official website, Magic Tree House books are for beginning chapter book readers.
Title: Magic Tree House (film)
Content:  Jack is a shy but confident bookworm and his sister Annie can quickly make friends with whoever she wants, both humans and animals. One day, while they were playing together in a forest, they unexpectedly stumble upon a wooden treehouse located in this forest. This magical treehouse allows people to travel across time and space whenever they liked. Morgan le Fay is accidentally transformed into a mouse named Peanut by Merlin (echoing the plot from books 5–8), and Jack and Annie have to find four magic medallions to rescue her. They visit the late Cretaceous period with dinosaurs (from book 1), a medieval castle (from book 2), the town of Pompeii (from book 13) and a pirate ship (from book 4). At the end, Peanut is once again turned into Morgan.
Title: Magic Tree House
Content:  The animated film Magic Tree House (マジック・ツリーハウス), produced by Media Factory, premiered in Japan in October 2011 and was generally released there on January 7, 2012. In 2016, Lionsgate acquired the film rights with a script by Will Osborne and Jenny Laird. The film will primarily contain plot elements from Book #29, Christmas in Camelot.
Title: Mary Pope Osborne
Content:  Mary Pope Osborne's most prolific work has been the Magic Tree House series. The series has sold more than 134 million books worldwide since its debut in 1992 and as of 2007 the series had spent a total 132 weeks on The New York Times Best Seller list. Owing to the successful sales of the books, Osborne for many years resisted efforts to commercialize the characters and books wanting them to live in the imaginations of children. The first of the Magic Tree House books, Dinosaurs Before Dark, was published in 1992. She was initially inspired to write the books while working in a teen homeless shelter and realizing that for the teens writing themselves into stories taking place in the Himalayas or Serengeti had a major effect on the teens. Osborne says she tried writing the book seven different ways before finding a way that worked." It 
Title: Magic Tree House
Content:  Her early work received mixed reviews. Her work includes young adult novels, picture books, retellings of mythology and fairy tales, biographies, mysteries, a six part series of the Odyssey, a book of American Tall Tales, and a book for young readers about the major world religions. Osborne says that she can work on Magic Tree House up to 12 hours a day and seven days a week and has used space at shared office space, The Writer's Room. She has modeled her writing after Hemingway by trying to be simple and direct and is "noted for writing clear, lively, well-paced prose in both her stories and her informational books."
Title: The Magician's House
Content:  The four books centre on young siblings William, Mary and Alice Constant. They spend their holidays at Golden House, a large, 16th Century house in the British countryside. The house is not give a specific location except close to Wales. The books follow the children as they discover the secrets of Golden House and the Magician who once lived there. The events of the four books take place roughly over ten months; with the events of each book occurring during a traditional British school holiday period. Effectively, each book reflects a season: The Steps up The Chimney takes place during the winter and over the Christmas holiday; The Door in 
Title: Magic Tree House
Content:  The Magic Tree House Fact Trackers (formerly called Magic Tree House Research Guides) are non-fiction companions to the fiction books, written by Mary Pope Osborne, Will Osborne, and Natalie Pope Boyce. They were first released in 2000 by Scholastic and Random House. They provide more in-depth follow-up information on the topics in the series than already covered. 43 have been published. The first two Fact Trackers were published in August 2000 as companions for the first two stories, then 7 to 8 years old. In 2008 story #39, Dark Day in the Deep Sea and its fact tracker #17, Sea Monsters were the first story and fact tracker to be published simultaneously.
Title: The Magic Key
Content:  The Magic Key is a series of books published for children as part of the Oxford Reading Tree, from Oxford University Press. The books are written by Roderick Hunt, illustrated by Alex Brychta, and primarily follow the lives of three children, Biff, Chip and Kipper Robinson, their parents, their grandmother, their friends, Wilf and Wilma Page, Nadim Shah, Anneena Patel and the Robinson's dog, Floppy. The series was first published in 1985 with a set of 30 stories, and there are now over 300. It is used by more than 80% of schools in the United Kingdom, and has been translated into numerous languages in over 120 countries. In 2000, it was made into a television series, produced by Collingwood O'Hare Entertainment and HIT Entertainment in association with the BBC.

Question: what genre is the magic tree house books?
Answer: Children's historical fantasy.