An author is the creator or originator of any written work such as a book or play, and is also considered a writer. More broadly defined, an author is "the person who originated or gave existence to anything" and whose authorship determines responsibility for what was created.
The first owner of a copyright is the person who created the work the author. If more than one person created the work, then a case of joint authorship can be made provided some criteria are met. In the copyright laws of various jurisdictions, there is a necessity for little flexibility regarding what constitutes authorship.