This story is about Robinson Crusoe, a stranded sailor who survives on an island by himself until he is rescued by civilisation. One way to see this story is that it is advocating individualism. After all, Robinson Crusoe can survive by himself on an island alone for 20 years, fashioning his own tools and domesticating his own animals.
Yet a closer inspection reveals that this is not the case. Robinson could not have survived without the supplies he obtained from the wreckage which includes weapons, ammunition, and various kinds of equipment. Although he eventually manages to produce a wooden shovel, it is obviously inferior to a metal one. He could not have produced a gun by himself, and spears are far inferior to guns for hunting. He also could not have domesticated the animals on the island if they had not been brought there by civilisation in the first place.
All in all a reader should get the hint that living alone as a savage on an island is vastly inferior to living within society with all the benefits provided by civilisation. Also one might wonder about how Robinson retains his language skills with nobody to talk to. In real life people usually become insane without company for an extended period of time.
Jonathan Swift wrote Gulliver's Travels as a parody of this book but he needn't have bothered. A closer analysis of this book is all that is required to understand its deeper meaning.
One might also notice that Robinson was in a deteriorating situation by the time he was finally rescued. He did not have a way of procuring gunpowder (where was he to obtain sulfur and potash) and he had run out of paper (was he about to start producing clay tablets?). Also, he had saved a man whom he later named Friday and taught him to speak English. This was a rather unrealistic turn of events and the reader should immediately recognise this.
Whilst one may be tempted to withdraw to a "log-cabin fantasy", the deeper meaning of this book is actually that man is nothing without society. One particularly obvious problem facing Robinson to anyone who had read the book was the question of how he was going to reproduce without any women around.
In conclusion this is a thought-provoking book that should be critically analysed to obtain its deeper meaning.