As a special Halloween-themed recommendation, I am recommending Coraline by Neil Gaiman.
Here's the publisher's description:
The day after they moved in,
In Coraline's family's new flat are twenty-one windows and fourteen doors. Thirteen of the doors open and close.
Coraline went exploring....
The fourteenth is locked, and on the other side is only a brick wall, until the day Coraline unlocks the door to find a passage to another flat in another house just like her own.
Only it's different.
At first, things seem marvelous in the other flat. The food is better. The toy box is filled with wind-up angels that flutter around the bedroom, books whose pictures writhe and crawl and shimmer, little dinosaur skulls that chatter their teeth. But there's another mother, and another father, and they want Coraline to stay with them and be their little girl. They want to change her and never let her go.
Other children are trapped there as well, lost souls behind the mirrors. Coraline is their only hope of rescue. She will have to fight with all her wits and all the tools she can find if she is to save the lost children, her ordinary life, and herself.
Critically acclaimed and award-winning author Neil Gaiman will delight readers with his first novel for all ages.
This book is not Halloween-themed, but it is a very spooky read. There are many creepy details, such as when the other mother is eating live beetles. However, this is a really good book! There are many interesting characters, some of whom are different in the world of the other flat, such as a snarky black cat who can talk in the other world. Coraline is an easily relatable character, since she is somewhat disgruntled about life but not mean. One of my favorite parts of the book is at the end, and, about it, I will say this: it is easily the scariest part of the entire book. Despite being scary, Coraline is not horrifying or overly upsetting, since otherwise I wouldn't have enjoyed it so much. All in all, this is a great read!