My 7 year old has just discovered these books and REALLY enjoys them. This series of books is perfect for an introduction to chapter books, the writing is simple and the plot is easy to follow for this age group. Jack and Annie are the two main characters, brother and sister who discover the Magic Tree House and go on all kinds of adventures together. I appreciate that they respect and even like each other, they aren't name-calling and being obnoxious, as I have seen happen in other series for this age group. I also like the fact that the author is sneaking in facts about animals and history, making this an entertaining and educational read for my daughter. Highly recommend!!