Allaah says, what means:

( Rather the devils disbelieved,
teaching the people magic )
[ al-Baqarah: 102 ]

And He sent angels to teach magic, testing the people's belief.  They would warn anyone who was interested in magic, saying:

( We are but a fitnah,
So do not disbelieve! )
[ al-Baqarah: 102 ]

Harry Potter books are all about magic.  The hero is a magician.  Magic spells and potions can be learned by reading these books.

For more details refer to the recorded lecture:

"The Reality of Harry Potter" (to be released soon on troid.org)