I loved the Magic Tree house books growing up. Now as an adult, I am slowly making my way through the series, a bit out of order.
I'm not sure if I ever read this one as a kid, but I loved it as an adult. A great adventure story and you finally get to meet the M person. Very exciting.
I also really liked the explanation for why Annie and Jack found the treehouse in the first place. They had to find it together, combining their personalities.
I'm so glad I went back and read this book. It really set up the future books in the series.
A great read.