Copyright
Definition 1 of 2
Pro Tip 1/3
Not Just Books
Copyright applies to various media, including music, art, and software, not only written works. The video game developer has the copyright for the game's graphics and code.
Pro Tip 2/3
Duration Limit
Copyright protection doesn't last forever. It typically ends 70 years after the creator's death. After the copyright expires, the book becomes public domain.
Pro Tip 3/3
Fair Use Exception
There are exceptions to copyright. 'Fair use' allows limited use, like for education or commentary. Students used the copyrighted song in a classroom presentation, which is fair use.