A work that falls generally within the subject matter of copyright (such as, a writing) must either qualify to be protected under federal law, or it cannot be protected at all.

In determining whether a substantial part of a work has been copied, the court must exclude from consideration any part of the work not properly the subject matter of copyright under s.3 of the Act.

In 1978, Section 301 took effect, preempting all state common law copyright claims that fall under subject matter in Section 102 (Subject matter of copyright: In general) or Section 103 (Subject matter of copyright: Compilations and derivative works) except for sound recordings fixed before February 15, 1972.