The particular courses offered in colleges and universities often also reflect the professors' convenience more so than the students' educational needs. For example, a history department may offer a course on the history of motion pictures or the history of wine-making, while not offering a course on the history of the Roman Empire or the history of medieval Europe, even though these broader courses would offer much more insight into the way Western civilization has developed and the way our world today has evolved. Because professors must do research in order to advance their careers, beginning with their doctoral dissertations, they must narrow their focus to something that has not been written about in great depth before. Then, having done original research or having made original analyses on such subjects as the history of motion pictures or the history of wine-making, a professor would find it much easier to teach a course on such a narrow subject than to do the vast amount of research required to teach a course on a subject as broad as the history of the Roman Empire or of medieval Europe--research unlikely to have any publication pay-off, since both subjects have already been widely researched and written about by others for generations. On many campuses, including some of the most prestigious, the disappearance of a meaningful curriculum, geared to the educational development of students, rather than to the convenience of career-advancement of professors, is a consequence of a proliferation of courses in narrow subjects. There may be a curriculum listed in the college catalogue but it can mean little if there are many disparate options for meeting a particular educational requirement--if, for example, a course on the history of motion pictures can be used to satisfy a social science requirement instead of a course on leading nations or empires of the world. Thus a student may graduate from some of the most prestigious colleges in the country fundamentally ignorant of history and all the insights and implications of history.