Books may be divided into three types:

• Good books
• Bad books
• Books which are neither good nor bad.

Try to make sure that your bookshelf is free of books which have bad content. There are books of literature, but they simply kill time without producing any benefit. And there are also harmful books which contain specific ideas or promote incorrect ideology - whether that is because the methodology, understanding of ‘aqeedah, revolutionary books should not be allowed on your bookshelf, because books nourish the soul just as food and drink nourish the body. If you nourish it with books such as those it will cause you a great deal of harm.

• Knowing the subject of the book: so that he can benefit from it, because he needs to specialize.
• Knowing the terminologies used in the book. This is what the scholars do in the introduction to their b...