The Bible says
Exodus 22:18 - Thou shalt not suffer a witch to live.
2 Chronicles 33:6 - And he caused his children to pass through the fire in the valley of the son of Hinnom: also he observed times, and used enchantments, and used witchcraft, and dealt with a familiar spirit, and with wizards: he wrought much evil in the sight of the LORD, to provoke him to anger.
Revelation 21:8 - But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.
So I think reading about them and 'likeing' them would be a sin. I've never read Harry Potter and there are lots of good books out there.
Here is a website that talks a little about how bad Halloween is.
link
1 Corinthians 10:21 - Ye cannot drink the cup of the Lord, and the cup of devils: ye cannot be partakers of the Lord's table, and of the table of devils.
1 Peter 5:8 - Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:
Ephesians 5:11 - And have no fellowship with the unfruitful works of darkness, but rather reprove [them].
Halloween is not about God or anything good. It's about ghost, witches, death and other evil things.
Ever think just what 'Trick or treat' means?
You will not go to Heaven for just believeing in God. You have to love him, keep his Commandments and live like you think he wants you to live. Read the Bible and accept what it says. If you know you're disobeying God and keep doing it, then you will not go to Heaven.
And if you are not sure about something then don't do it. It's better safe then sorry. And pray about it. If you really want to know the truth, God will not give up on you.
Matthew 7:7-12 -
Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you:
For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.
Or what man is there of you, whom if his son ask bread, will he give him a stone?
Or if he ask a fish, will he give him a serpent?
If ye then, being evil, know how to give good gifts unto your children, how much more shall your Father which is in heaven give good things to them that ask him?
Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.
And for people who say all you have to do is believe, remember that even the Devil believes in God.