As with any work of literature, there are several themes that can be identified in Golding's Lord of the Flies. When looking to form a theme, a reader should first consider the one-word topics that emerge from a text before giving an explanation of how that topic is used in the text in a thematic structure. In Lord of the Flies, the conflict between authority and the individual is at the forefront of the plot, so it can be used to form one of the prominent themes in the novel.
Once the boys crash on the island, they are removed from the typical cultural authorities such as family, school, and government. So, they initially cling to the hierarchical structure that they are used to by dividing into groups and using the conch shell as a "call" to unity. However, as their time on the island progresses, the boys become more animalistic in their behaviors, which eventually leads to the replacement of Ralph as leader, the shattering of the conch shell, and the deaths of Simon and Piggy. Thus, the theme emerges from this complex work that human beings require a governing force to support and restrain them from their own individual evil desires.