I had heard a lot about this book. Originally, I'd heard about the Italian film, then the American re-make, and found it all started with this book. It's the perfect October read. It's scary on multiple levels (from violence, to pedophilia, to gore) and I think it handles these topics well and with the respect they deserve. It isn't a easy read, but it is very rewarding if you can get through it. I also appreciate how it's set in the 1980's, that way it isn't bogged down with modern devices and having to work around those. Yes, there are some weird translation issues (words not making grammatical sense, or simple words missing), but the writing overall makes up for that. 
In the back of my copy there's a page advertising John's next book. I don't know if I'll read it, but Let The Right One In is a book I will keep on my shelf.