Yes. Since the readings are chronologically sequential, and the Greeks are foundational, the ideal way to take the entire course is first Greeks, then Romans the next year, etc., over four years. However, we do have students taking more than one level at a time. Usually they do Greeks and Romans, then the next year they do the Middle Ages and Moderns. So while for most students we recommend doing one level a year to maximize the order of discovery approach,  since each Great Book does stand-alone (part of what makes them great), we do allow students to take whatever levels they wish. We encourage the study of the great classics of Western civilization, so if someone is fired up to do more than 30 great books a year, more power to them.