Hey, what have you done? Why did you photocopy that textbook?
Why? Why not? Did I do something horrible?
Oh, you! Don't you know copyright? That is absolutely violating the law!
The textbook you photocopy has a copyright protection.
What are you talking about?
The author registered their work so that they can protect their works from others that uses their work, and gains profit without their permission. They have the right to their works and can decide if and how others can use their creation.
That is what I am talking about. That is actually like stealing. If you did not create it, you do not have the right to use it freely.