Underline book title. essay help.?

Yes, it does have to be underlined if you are referring to the book. If you are using the phrase "lord of the flies" as a symbol, then no, it does not have to be underlined. But every time you refer to the book, make sure to underline it. And dont put it in quotes either. That is a common mistake that I often see. You are supposed to put something in quotes when it is a shorter work of literature, not a book. So to answer your question specifically, yes, "Lord of the Flies" should be underlined in the second paragraph.