Beth C.
This is the first in a series, and it's entertaining. There are actual monsters in this book, and - I would presume - those to come. They're *just* scary enough, without being something that's going to terrify every kid into sleeping with mom and dad. Actions have consequences, and they learn this during the course of the story. The siblings are interesting and typical at the same time - they travel and see things many others don't, but they have to be separated in the car to stop from kicking each other.
Overall, I'm looking forward to reading the second one (I work at a bookstore and try to keep up on kid's titles), and I will happily recommend this title!