I finished this book in one sitting and I liked it, but I'll admit that I couldn't help but get the feeling that this heavily referenced some of Gaiman's other works that I hadn't read. Well, more heavily referenced, in any case. I knew going into this that it was likely that he'd drop little bits or references to his other works. Gaiman has been known to do this, after all, but I couldn't quite help but feel that I'd probably have gotten more out of this if I'd read some of the more recent stuff he's done. 
 In any case, this is an excellent book. It doesn't last very long and I'd say that most readers will be able to finish this in one sitting, probably long before they've even had a chance to finish whatever tasty beverage they have beside them. The story here is fairly simple. You have a kid that stumbles upon magical neighbors and accidentally brings over something that is intent on making his life miserable and taking over his family. His family is blissfully unaware of the danger that this person/creature puts them in, or at least is unaware of the danger for our young boy. 
 This is magical, but at times the horror here is really much more mundane than magic. The threat Ursula (the baddie) poses is something that a lot of people might relate to: she's not only taking over the family and putting herself in the mother's place, but also manages to be mean to the boy (we never really know his name) without any repercussions from his parents or sister. There's something a little creepy about a creature that is pretty much ripping your home life apart in ways that have nothing to do with casting dark magical spells against everyone or turning them into frogs. Instead you have your main character feeling like it's "them versus me" for much of the portion where Ursula is a big threat. 
 I'd complain about this being short, but then I think that this is exactly the length it should be. There's the potential for more books surrounding Lettie and her family, but for now this story is very well summed up in just over 100 pages. It's really a nice read and one I'd definitely recommend for Gaiman fans.