No dates are specifically mentioned in Lord of the Flies, but the story takes place in the future during an era of wartime when an apocalyptic atomic destruction seems imminent. Golding based his story on his own experiences during World War II, and it can be assumed that the story takes place during the oft-expected third world war (probably occurring some time after WWII or after 1954, the publication date of the novel). The island on which they are stranded is also unknown--it could be anywhere from the Caribbean to the Pacific. The boys live in an atmosphere of complete minimalism, with nothing more modern at their hands than the glasses which Piggy wears. The only suggestions of the modern world come from the references to airplanes--they crash-landed near the island and they hear planes overhead on occasion--and ships, on which they hope to be rescued.
William Golding wrote Lord of the Flies based on his own experienes at the start of World War II. The novel takes the reader through the torment of good vs evil similar to the Nazi vs the Allies. The young boys digress from the good upbringing of the British society to the evil destruction of each other and the island in the fashion of war. Other subheadings might include Good vs evil, the destruction of man, perhaps the adults as the teachers of evil, the older boys (Ralph, Jack, Simon) as the doer of evil, and the younguns as the learners of evil. The continuation of life or evil based on what is taught.