Mortimer Adler has observed that great books are popular and not pedantic. He has the following points. According to him great books are not written by specialists for specialists. They are written for common people and not professors. Whether they be history, philosophy, science or poetry they treat human and not academic problems. They treat the elements of any subject matter and so they are elementary by nature. They are not related to one another. Neither are they graded like text books. Great books need no prior reading. For such reasons they have remained popular.