Final answer:
The use of dramatic monologue in "My Last Duchess" allows the reader to hear the Duchess's thoughts and desires.
Step-by-step explanation:
The use of dramatic monologue in "My Last Duchess" by Robert Browning is effective because it allows the reader to hear the Duchess's thoughts and desires. The entire poem is spoken by the Duke, who reveals his thoughts and feelings about his late wife. Through his monologue, we gain insight into the Duchess's personality, her relationship with the Duke, and the Duke's possessiveness and control over her.