Defoe's novel features first-person, retrospective narration: the story is told by Roxana, from her perspective, using "I", "my" etc., and includes access to her inner thoughts and feelings. Importantly, while the plot spans the entirety of Roxana's life, it is narrated as she looks back and remembers the earlier events of her life. This technique is similar to a fictional version of memoir or autobiography; in the eighteenth century, this type of writing was a key way that the novel became a popular and widely read form of literature. This retrospective narration allows Roxana to distinguish how she felt about key events at the time when they were occurring versus how she came to feel about them later. For example, Roxana often describes past relationships as sinful, but at the time when they were occurring, she did not necessarily feel that way.
Roxana's narration affects the way incidents are presented in the novel: the chronology is not always strictly linear, and sometimes additional details are added as she remembers something. Significantly, Roxana presents an early example of a trope that would go on to become important in later novels: the unreliable narrator. Literary critic Wayne Booth coined this term in his 1961 book The Rhetoric of Fiction. When a story is being told by someone who is also a character in the story, they might not always present a totally objective account of facts. They might instead make assumptions or misrepresent their motivations; an unreliable narrator might even omit or leave out key pieces of information, or attempt to lead a reader to reach particular conclusions about a situation. For a reader, this type of narration can add richness, suspense, and complexity to a work of literature. Examples of unreliable narrators in fiction range from the governess in Henry James's Turn of the Screw to Amy Dunne in Gillian Flynn's Gone Girl, and this narrative device also appears frequently in films and television shows.
When Roxana describes events from her life to the reader, she often has a motivation to present these events in a particular light. For example, Roxana recounts that it was Amy who first suggested to her that she begin a sexual relationship with the Landlord/Jeweller, and that she was initially horrified and reluctant at the idea. This representation of a pivotal choice in her life foreshadows a later, and darker, incident: Amy will suggest that they kill Susan to avoid having their true identities and histories revealed. Roxana assures readers that she was horrified and discouraged this idea. However, both of these actions have a great deal of potential benefit for Roxana, and at other points in the novel, she reveals herself to be callous and calculating. Roxana's account might be curated to establish her lack of moral culpability. Roxana also presents herself throughout the novel as a repentant sinner, and someone who now looks back and sees all of the mistakes that she made. This focus leads her to shape her story towards a particular perspective, and recount events from a specific point of view. Many of these features have become familiar elements in fictional narratives, but when Defoe was writing, these devices were a new and innovative feature of the rising form of the novel.