I have not read the book, but since I have seen two versions of the story and they are both fairly similar, I can say that I know what it is about now. I have to say that the Christmas released British version was not exceptional in any way, even if casting Christopher Eccleston and Robert Sheehan from the Misfits.
The story is about a race of small humans that live underneath the floorboards of a house and "borrow" stuff in order to survive. They are basically human vermin, but intelligent and benign. The focus of the story is Arietty, a borrower teen girl who wants to explore like her father and therefore exposes her family to the human "beans" and almost gets them killed. In the end, all is good.
I have to say that the Japanese version was much better, even if from Hayao Miyazaki's animations it was probably the weakest. I can't stop from thinking that the story itself is not very good, due to its simplicity and lack of character development, but not having read it, I cannot give an informed opinion.
Bottom line: a small fairy tale like story, but not exceptional and a wee bit boring.
