Writers can adapt or incorporate someone else’s work into their own if one of the following conditions are met: (1) if the existing work is in the public domain, (2) if the use constitutes a “fair use,” or (3) if the writer has a license to do so. ...
Registering the copyright in your work with the U.S. Copyright Office is the one and only way you can avail yourself of the various rights and remedies provided by U.S. Copyright Law and defend your work against infringement.