The main themes of Defoe's Roxana are morals and economics. These two are causally and conceptually related: while moral issues pervade the entire work, literally down to the last sentence, Roxana and her maid's morals are constantly compromised for money. Amy's dictum in life—“comply, survive; defy, die”—is something both women followed. At first, Roxana decides to become her landlord's mistress because her husband has abandoned her, leaving her destitute and in utter poverty. But her later decisions to give her body for considerable sums of money, stocks and property are obviously motivated by greed and ambition.

But Defoe was considerably more complex than what one would expect from a pragmatic entrepreneur in the early eighteenth century. The plots of Roxana are arranged so that the title character's behavior is arguably justifiable. She comes close to annihilation when abandoned by her husband and she resolves to never let herself be financially vulnerable again. Having made herself a fortune, courtesy of two lovers, she would never again hand over her finances—and her freedom—to a husband. Financial security becomes an obsession for Roxana. Once she is able to successfully negotiate the transactions with her first keeper—her landlord—subtly seducing him with her charm, wit and sexuality, she is on a set course to prosperity. Throughout her dealings with men—the landlord, the French nobleman, and the Dutch tradesman—Roxana is never under any illusion that she is behaving morally. In fact, through her many ruminations and self-criticism, she continuously reminds herself that she is “a whore.”

Self-reflection on moral issues and repentance seems to be an important aspect in all Defoe’s narratives. Robinson Crusoe, who had gone to the ill-fated sea voyage against his family’s wishes, bemoans his lack of obedience and asks forgiveness from God many times. But Roxana, who also has the capacity for self-reflection on moral matters nevertheless is able to give perfectly logical reasons to justify her actions. If Milton justifies the ways of God to men in Paradise Lost, Defoe seems to be justifying the ways of women to God. Time and time again, Roxana confronts the moral implications of her actions. The power of her reasoning to defend herself is impressive, especially because she invariably ends up admitting her moral liability, but insists that in her society, with the problems a woman faces, there is no other way: comply and survive; defy, die.

The moral issue in Roxana can be further subdivided into the following categories: sex, marriage, and motherhood. Once again, like a typical early Augustan writer, these concepts are conceptually and rationally interrelated.

It was Bonamy Dobree, an eminent scholar and critic of eighteenth-century English literature who first commented on the extraordinary treatment of sex in Roxana . According to Dobree, it borders toward the erotic. Interestingly, Defoe must have been well aware of the erotic passages. He wanted to be truthful to the history of this woman he was writing about, he says in the preface. “If there are any parts in her story, which being obliged to relate a wicked action, seem to describe it too plainly, the writer says, all imaginable care has been taken to keep clear of indecencies and immodest expressions; and it is hoped that you will find nothing to prompt a vicious mind, but everywhere much to discourage and expose it.” Still, the author seems troubled about the erotic nature of parts of this book. Toward the end of the preface, he puts the blame squarely on the reader: “Scenes of crime can scarce be represented in such a a manner...

When Roxana is next confronted with the proposal of marriage, years afterward, when she has already been a seasoned mistress to three different men, she flatly turns him down saying that she would never again be a wife to anyone. The long discussion that follows, creating an interesting debate on whether women of fortune should marry for the sake of security.

The discussion begins when the lovers, Roxana and the Dutch tradesman, are in bed and the man asks her why she refuses to be his wife, why, if she has given him her most intimate gift, she refuses to make him “her own.” Roxana replies simply: she does not want to lose her liberty; no other reason. The tradesman, however, genuinely loves her and is not willing to accept such a simple answer. In the end, he broaches the sensitive question: is it because Roxana thinks that by marrying him she would have to give up her wealth to him? He promises her this will not be the case. He would not lay claim to one pistole of her earnings and that she would be free to bequeath her money to whomever she wished.

Roxana is silenced by this question. Indeed, it is true. She is nothing if she was not a complex woman, capable of intricate thoughts and deep self-reflection. Quickly, she realizes that if she admits the truth, she could seem as an entirely unscrupulous woman, one who would rather give up her virtue and expose herself naked to a man than give up her money. No, she could never admit to that. So she takes another route.

There upon follows a long argument between the two. The man insists that she would not lose her freedom, but Roxana is a realist. She believes his sincerity but cannot ignore what really happens in marriage: that the very nature of marriage contract makes the woman “a slave.” The man gives several arguments in favor of husbands. It is the husband who has to be the breadwinner, he says, whereas the wife, for all her subjugation, simply spends his money. They argue, back and forth, until the tradesman promises that should Roxana be his wife, she would manage the family’s finances, not he. Regardless, Roxana is not convinced and sarcastically berates her lover for allowing her to run the family’s finances. The wife is a mere “boy,” in the family ship, says Roxana; the husband is “pilot.”

It is, therefore, somewhat ironic that toward the end of the story, Roxana does become his wife, and, not soon after, he discovers her deceit.

Connected to marriage is the theme of motherhood. During the course of the story, Roxana has eight children, none of whom she raises herself. This tendency to dispose of the children is quite common in Defoe’s fictions. Other characters, like Moll Flanders, have done it. In Roxana, the first five children, all from her first and only marriage, are given away to relatives out of financial necessity. But even then, the dexterity with which she and Amy get rid of them is quite remarkable. Somehow, Roxana, throughout the fictitious history, is unusually matter-of-fact when relating the status of her babies. For instance, when Roxana leaves Holland for England, having broken up with her Dutch lover, she seems to be quite content leaving with “money in my pocket and a bastard in my belly,” as she describes her situation. One gets the impression that to Roxana, nothing matters except her lovers as a means to get rich.

Economics is the next most important theme of this work. Having learned too early in her life the importance of money, money becomes almost a fetish to her. There are several instances in this work where Roxana, having collected the money from her departed lovers, sits down to count her gold almost moments after regretting the death of one of her lovers or the departure of another. Defoe, of course, was a business man and an entrepreneur, and, as such, understood the value of money. In Robinson Crusoe and Moll Flanders there are many instances of counting: counting goods from a wrecked ship, or counting gold pieces. Keeping ledger is an important motif in Defoe’s fiction. Human relationships are intricately connected with economic relationship.

Thus, in Roxana, our so-called “fortunate mistress” is constantly in search of gold. No amount of money seems to be enough for her. Not only does she “earn” the money using her body, she also spends judiciously, spending well and saving much. Therefore, her acquaintance with Sir Robert Clayton, the economist, makes for an unusual and rather interesting reading. It adds not only to the realism of the work but also gives us an insight to Defoe’s economic mind.

By the time she returns to England, Roxana is phenomenally rich. She meets Sir Robert Clayton, a wealthy man, who, for a change, seems to have no romantic or sexual interest in Roxana. All he is interested in is showing her how to invest her wealth, how to double it and triple it. Defoe goes into the details of investment and in lay person’s terms. Sir Robert explains to Roxana how she can save and invest. Introducing terms like “capital,” “family economy,” and "the scheme of frugality," Sir Robert shows Roxana how she can become one of the richest women in London.