S/Z is the first work of proper “lit’r’y theory” I ever picked up. It was a required course for comp lit majors, and I have my suspicions that this was the first work listed on the syllabus precisely so that we could take the appropriate advantage of drop/add week. Years later, and after having read much more of notre cher Roland, I came back to it, and I have a theory of my own. That it’s probably the most important book you could ever read if  you are invested in the study of literature. Particularly if you want to teach literature. This theory has a secondary component, which is that S/Z can also devolve pretty significantly if not done correctly.