A letter is not a dialogue or even an omniscient exposition. It is a fabric of surfaces, a mask, a form as well suited to affectations as to the affections. The letter is, by its natural shape, self-justifying; it is one's own evidence, deposition, a self-serving testimony. In a letter the writer holds all the cards, controls everything about himself and about those assertions he wishes to make concerning events or the worth of others. For completely self-centered characters, the letter form is a complex and rewarding activity.