I actually started reading this Thursday night --- I didn't get to sleep last night so I finished it. This is a really great book. Our protagonist, Will, meets a family that is part of a hidden Grimm tale. The family is worried about letting him and a friend know, but Will starts working on helping. Over a period of years, we not only meet fairies, bird-headed people, and six-inch people, but people related to an event almost a hundred years before. Will, with the family, has to make a lot of difficult decisions.
This has some light simularity to Jo Walton's Among Others as well as Katherine Blake's (Dorothy Heydt's) The Interior Life, but it is more modern, even though it starts in the hippie era.
The cover is wonderful.
I really really like this, the way I like the other book I have of hers, Dark Cities Underground. I'll have to read that again soon.