Robert Browning's dramatic poem "My Last Duchess" defines how extremely a person may lose touch with reality, as a result of jealousy and self-love.  This central thought is achieved through an aristocrat's conversation with a visitor concerning a painting of his ex-wife; within the conversation, the aristocrat--Alfonso II, Duke of Ferrara--reveals that he has been a key figure in the murder of his late wife.  The Duke's sense of reality and his misuse of power stand as important facets within the fabrication of the central idea.

The Duke almost seems to be encouraging the reader to focus on the fact that his sense of reality is defective.  He begins pressing this notion to the reader within the early stages of the poem, while talking to the visitor about a portrait of his murdered wife: "I call that piece a wonder now...