This book offers a theoretical framework and numerous cases studies - from early comic books to contemporary graphic novels - to understand the uses of genres in comics. It begins with the assumption that genre is both frequently used and undertheorized in the medium. Drawing from existing genre theories, particularly in film studies, the book pays close attention to the cultural, commercial, and technological specificities of comics in order to ground its account of the dynamics of genre in the medium. While chronicling historical developments, including the way public discourses shaped the horror genre in comics in the 1950s and the genre-defining function of crossovers, the book also examines contemporary practices, such as the use of hashtags and their relations to genres in self-published online comics.