These books have been returned by other students and cost less than new books. Also, at the end of the semester you can sell your textbook back to the bookstores for a small amount of the original cost. Most classes that you will attend, especially as a freshman or sophomore, will be lecture courses. These courses can be quite large, 40-150 students, and the professor or teaching assistant will do almost all the speaking. You will be expected to read the textbook at home, take notes during class, and understand all the material in order to take exams.
Some students tape the lectures or even put the lectures on their laptop computers during class.
Sometimes the professor will have smaller study group sessions where you can come and ask questions if you are having trouble. These sessions are usually scheduled before an exam. Not all lecture classes are large. Some classes are smaller and the professor expects you to participate in class discussions. These classes are intense discussion courses, usually covering a limited, specialized topic.