17.4 Copyright-Subject Matter-Ideas and Expression refers to the concept that ideas, facts, and expressions are protected by copyright law, but not the subject itself. This concept is often referred to as the "idea/expression dichotomy." This means that the copyright law protects the expression of an idea, such as a book, song, or artwork, but not the idea itself, such as the plot of a book, the melody of a song, or the concept of a painting. Different types of 17.4 Copyright-Subject Matter-Ideas and Expression include literary works, dramatic works, musical works, artistic works, films, sound recordings, broadcasts, and computer programs.