Can I know if it is Haram to read books like Harry Potter?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.

It is not permissible to read novels that include Sharee‘ah violations such as promotion of corrupt beliefs, vices and unlawful practices, and negatively affect the Muslim’s creed or his morals. It is not permissible to read them or to waste time on them except for a purpose that is considerable under the Sharee‘ah – like refuting and criticizing them – by someone who possesses Islamic knowledge and sufficient faith that secures him against being affected by the deviations included in such novels.

As for fictional stories that are free of such Sharee‘ah violations, the basic principle is that it is permissible to read them. However, it does not befit a Muslim to indulge in that and waste his life in something that do not bring him any benefit in this life or in the Hereafter.

The novel that you mentioned is based on glorifying magic and beautifying it. Accordingly, it is not permissible to read it except for a Sharee‘ah-considerable purpose as mentioned above.

For more benefit, please refer to Fatwa 87235.

Allah knows best.