RU Level: 2nd Grade
There are actually two different groups of "Magic Tree House" books. Books 1-28 describe Jack and Annie Smith being sent on different adventures to historical or current, actual places by Morgan Le Fay. These books are shorter. Beginning with book #29 the children receive their missions from Merlin the Magician and have two additional characters join them: Kathleen and Teddy. These missions are sometimes to mythical, fantastical places, are longer, for more advanced readers, and are often referred to as the Merlin Missions. The Merlin Missions now go through book #55. Recently the author has written three more books as part of the original, shorter, Morgan Le Fay series: A Big Day for Baseball (2017), Hurricane Heroes in Texas (2018), and Warriors in Winter (Jan. 2019). With the recently published reprints of these books, the two groups have been divided into two different series and numbered sequentially. This means there is a #1 Original Series and a #1 Merlin Mission Series. While it makes more sense to read them sequentially, If it all is too confusing-- just enjoy reading the books!
Don't forget about the "Magic Tree House Fact Tracker" collection with non-fiction books that correlate with the non-fiction titles, providing factual information about the time/place of the adventure. These are also on the 2nd Grade Level.