In this library, there are thousands of books about the magic spells and mroe. Also, there are some books that were included in Restricted Section. Most of the books were in Restricted section were about darkes and evil magic. Restricted Section is not allowed to students to read.
Additionally, Harry knew about Horcruxes which is the worst object in Harry Potter in this library.
The reason that I want to go to the Hogwarts Library is to go and read the books that were in the restricted section.
go back