There are two ways to enter:
If you live in a place where you can enter in both...feel free to do so. For those outside the specified countries, you'll actually have two ballots entered in my drawing (the software that takes the poll will determine what country you are from). This way everyone will have two chances to win.
Even if you've read Hollow World, or have your own print copy, I encourage you to enter. The books will arrive in time for holiday gift giving so you might just get a nice present for a friend or loved one.