Neil Gaiman is not spooky by default (proof).
However, some might say that he is quite good at spooky-type things. His 2008 novel The Graveyard Book won the Newbery Medal, which is not given according to the goodness of a book's spookiness. However, if he had done a really, really bad job of writing a spooky book, I doubt he would have won the Newbery, the Hugo, the Locus, and the Carnegie. Gaiman actually has a bad habit of winning Locuses, but that isn't the point.
My point is that Gaiman is a pretty safe place to turn for some spooky reading around Halloween time. Wrap yourself up in your cloak, get a mug of hot chocolate, turn the lights down, and read about the life of Nobody Owens, growing up in a graveyard.
Or you could read his award-winning novella, Coraline. I find that Coraline is more terrifying than The Graveyard Book. I enjoyed the latter, but due to all the things that happen in the world behind Coraline's door to nowhere, I was for the longest time somewhat wary of an extremely shallow closet that I never opened because it looked like double doors to nowhere.
Yes, I am a grown woman.
Gaiman also writes other things. Like American Gods and Sandman and a bunch of short stories. But for Halloween, I think I'll go with the kids' books. They may be all I can handle.
Now tell me, what will you be reading after you turn out the porch light and head back inside to eat the rest of your Halloween candy?