Although the original title of Robinson Crusoe is, "The Life and Strange Surprising Adventures of Robinson Crusoe", it is in fact a fictionalized account of a man's life. A man named Robinson Crusoe, who experienced these adventures never lived.
In the story, Robinson Crusoe is the narrator who takes the reader through a sea-faring adventure story to a a deserted island and back to London again. He comes from a middle class background and has displeased his family by taking to the sea. The reader gets to experience his character change as he starts out not so brave and certainly not prepared to survive on an island alone. He learns to survive and conquer his own fears and to communicate with the native he rescues, Friday.
By the time he is rescued (an exciting adventure in itself as he rescues and liberates a crew of European sailors from natives) and returns to London, he has come full circle and is able to get married and thereby fulfill the expectations of his middle class up bringing.