The reason a comma is put in between the book titles is because, while they are in quotation marks, they are still part of a list. When listing things, you put a comma in between each item. For example, if you were to say “He likes bananas, oranges, and carrots”, you would have to put commas between each item that “He” is said to like. How these commas are placed is a matter of debate for some people, since many are starting to avoid using the Oxford comma. If you do not use the Oxford comma, the sentence would read “He likes bananas, oranges and carrots.”
One reason for the overwhelming popularity of the play throughout the ages is that it focuses on two people who defied society in order to follow their own hearts. Shakespeare scholar Walter Cohen cites the popularity of Othello during times of great rebellion and upheaval; the play was most popular during the European wars of the mid-19th century, the fall of Czarist Russia, and also during World War II in America. These productions tended to emphasize the nobility and love of Othello and Desdemona, and made their fall seem more tragic and ill-deserved.