I loved the Magic Tree House series growing up so when I saw this book in the Little Free Lending Library, I had to read it.
It is the same fun, educational stories that I remember when I was a kid. This is such a great series. It is a good combination of fact, adventure, and friendship.
While it is book 23 in the series, it can be read as a standalone because the prologue pretty much catches you up on what's going on. But I am sure it is better if you have read the preceding books (I will have to be on the lookout for them).
I like that Jack and Annie had an actual mission to complete. From what I remember from the first few books, they just traveled through the books, which was interesting, but this is a good progression for the series.