Robinson Crusoe extended the form of the picaresque and turned an adventure tale into a critique of colonialism. Moll Flanders did the same with the class of 'gentlewomen'. Roxana similarly has come to be accepted as a critique of early capitalism -- a time in English history when the industrial revolution was yet not a tactile reality but a creepy creature whose tugs on morality, civility and social infrastructure were being secretly felt. Defoe takes a old world morality tale about a woman's coming to terms with her own profession as a whore and turns it into a contemporary tale about capitalism's philosophy of self-aggrandizement and saleability of the self.
In retrospect Defoe will seem prophetic in his constitution of the plot about Roxana's willing acceptance of her profession and how she readily agrees to 'capitalise' it when she knows her moral degradation is irreversible. In medieval morality plays, Roxana's good self would have been saved by a benign god who in a climactic moment would retrieve her from misery. But in Defoe's world emergent capitalism prevails over frivolling morality and what would have been a fallen life before becomes a life of opportunities for Roxana.
No wonder Roxana is called Defoe's 'darkest' novel and that explains the crowd of critical and scholarly attention that it has received. The term 'dark' is not a secular word and hence burdens the novel with a given morality and wisdom. By such means it is easy to provide an ordinary, feminist framework for Roxana and turn it into a conventional male author's depiction of a bold woman, too much in control of her sexuality and hence too obviously susceptible to moral decrepitude and eventual fall. But at another level Roxana is a mock tale about capitalism, corruption and individual enterprise.
As the novel proceeds, we see Roxana triumphant, outwitting the males in her life and by using them to achieve her own purposes. Later, she is seen to be felled again and reverts to her previous status of misery and helplessness. At one level if this is her punishment for living against the moral standards of the society and the fantasy of a protestant moralist, at another level it is a critique of the