This lesson deals with copyright duration, an arcane, technical and somewhat laborious subject that is not always covered in depth in copyright law or intellectual property law courses. Therefore, it is assumed that this is the student's initial exposure to the subject matter. Nevertheless, copyright duration is one of the few areas of copyright law that is filled with certitude. After divining the relevant background information concerning the creation of a work, including manner of authorship responsible for creating the work, the specific date on which copyright protection for a work has or will end can be determined. Only copyright duration under United States copyright law is addressed.