Arthur Miller highlights the relationship between Eddie and his adopted niece, Catherine, showing it as the most important theme in the play around which all events result. Eddie, the protagonist of the play as reflected in the ancient Greek drama, is an ordinary good man; hard-working, generous, and sincere; but has a flaw inside him which is his weakness in controlling his exceeding love for Catherine.
The playwright emphasizes how Eddie's love for Catherine is not as the normal love of father for child, but that he is in love with her in his overprotectiveness and attempts to control her in everything. This unlawful love first appears in Eddie's obsessive concern with Catherine's appearance and way of dressing: "I think it's too short," he says of a skirt and "Katie, you are walkin' wavy! I don't like the looks they're givin' you in the candy store. The heads are turnin' like windmills.".
These symbols in Eddie's mind represent a version of femininity he tries to protect her from as he is jealous of other people seeing her and he wants to keep her to himself.
Moreover, Eddie tries to control Catherine and restrict her from going to work. He doesn't want her to communicate with people and in doing this he stifles her freedom and destroys her personality. Beatrice opposes him: "I don't understand you, she's seventeen years old, you gonna keep her in the house all your life?"Catherine, however, is naive at first and unaware of the reasons behind Eddie's overprotectiveness and obsessive love for her. She respects him and doesn't like to upset him; she is almost to tears because he disapproves of her dress and appearance. She shows care for him in the way she seats him and offers him a beer, or later lights a...