This work examines how the definition of the medium, as well as its language, readership, genre conventions and marketing and distribution have kept comic books within the realm of popular culture. This study seeks to provide a contribution to the current literature on comics and helps clarify concepts and definitions useful in studying the medium. The evolution of the comic book superhero - from the patriotic heroes of the 1940s to the muscular rebels of the 1990s - is analyzed, showing how as the superheroes change, so does the style and content of the books.