For film studies, the book defines genre as a category or classification of a group of movies in which the individual films share similar subject matter and similar ways of organizing the subject through narrative and stylistic patterns. Additionally it can also function as cultural rituals in which rituals are both formal and ideological practices that can become a beneficial means of responding a variety of situations. Genres have been used to classify various art forms well before the creation of films. For literature, Tragedy was considered the most important in Aristotle's Poetics, Musical genres were composed of classical sonatas and symphonies, and genre painting depicting domestic life and daily social encounters began to surface in the 17th century and were then followed by genre painting that came to suggest an image of a "slice of life. Ultimately these genres were linked to the stage, and the most popular genre of the 19th century melodrama was formed. Through the creation of these different forms, three function began to tae shape: to provide models for producing other works, to direct audience expectations, to create categories for judging or evaluating a work. From the beginning, cinema has employed the genre system, but the rise of the Studio System in the 1920's and 30's basically opened the door for movie genres. It adapted an industrial mass production format, which allowed for movie producers to reuse script formulas, actors, sets, etc. to create modified version of the same popular film. The Studio System soon saw its decline in with the Paramount decision of 1948, where the Supreme Court rules that the major studios violated antitrust laws by also owning movie theaters, which allowed them to monopolize the film business. As time passed, a new era known as New Hollywood began to emerge. Film school educated directors began drawing on established genres, special effects and large advertising to create blockbusters.