The most important aspect of any course, the holy grail of answers to all your questions, is the textbook specified for that course. Although you might have to use a significant amount of reference materials & case studies to actually get a grip of some of the concepts, the biggest help you can get is from your textbook. But what do you do with your old books once you're done with the course? What do you do when you have no more use for the book & it is just gathering dust sitting on a shelf in your book cabinet, with all the other textbooks that you no longer need? Since you no longer use those books, the best thing for you to do is sell college books to either a bookstore or maybe a fellow student who is taking the course after you.