At the literal level, Lord of the Flies, is a gripping tale of a group of British schoolboys, aged six to twelve, stranded on a desert island, having to organise and fend for themselves until they are rescued. They were being evacuated from their schools in the colonies, but their plane crashed far out in the ocean. There is no adult to lead them. Initially they organise themselves well, but gradually their society disintegrates and they - or most of them - end up as complete savages. The author, William Golding, intended the scenario to be perfectly realistic. He commented once that the novel grew from the brutalities he witnessed during his service in the navy during World War II and from his thirteen year's experience of teaching young boys. He certainly succeeded in giving the boys clearly-drawn and complex characters and in making their interaction most believable.
But the novel is also an allegory - a story which has another meaning beyond the surface one. We may take Ralph to symbolise common sense; Piggy, intellect or scientific knowledge; Jack, tyranny; and so on. And thus we have an allegory of the perennial struggle of humanity's higher faculties against its baser instincts (the will to power, the preference for licence over liberty, etc.). Some critics have also discovered in this text allegories of the whole development of social forms from primitive times to the present, or of the growth of totalitarianism in Europe in the 20th century. .
We can also talk of Lord of the Flies as a fable - a story which illustrates a moral. Golding is evidently saying that evil is inherent in humanity, that whereas we usually try to see it as something which lies outside ourselves, in reality it lies within. .
This novel fits into the 'survival narrative' tradition, where a person or group of people are placed in a strange, and usually primitive, setting, and the values of the writer's society are put to the test.