To obtain a copyright, the woke must be original,but it may be substantially sikilar to work previously written or produced by others.Many authors,for example,have written biographies of Thomas Jefferson. While each is copyrighted,that fact does not preclude other authors from writing biographies of the same man.A copyright of any work created after january 1,1978,lasts for the lifetime of the author plus 50 years after the author's death