A Certificate of Authorship ??? Writing for a Motion Picture is an official document that is issued to the writer or writers of a motion picture, acknowledging that they are the authors of the script for the movie. This certificate is typically issued by a motion picture studio, producer, or distributor and is essentially a form of legal recognition that the writer or writers are the rightful owners of the copyright for the script. There are two main types of Certificates of Authorship for Writing for a Motion Picture: the Writers Guild of America Certificate of Authorship and the International Alliance of Theatrical Stage Employees Certificate of Authorship. The Writers Guild of America Certificate of Authorship is typically issued by the Writers Guild of America when a writer or writers have registered a script with the guild. The International Alliance of Theatrical Stage Employees Certificate of Authorship is typically issued by the International Alliance of Theatrical Stage Employees when a writer or writers have registered a script with the union.