Tennessee Williams uses the technique known as "breaking the fourth wall," when a fictional character talks directly to the audience and thereby breaks through the invisible screen that separates audience from characters, by having Tom speak directly to the audience.
"When ''The Glass Menagerie'' opened in New York in 1945, some people objected to Tennessee Williams's breaking of the fourth wall by using the character of Tom, the Williams surrogate, as the narrator. Tom's comments probably aren't necessary, said one critic dismissively. Not necessary? The narrator's vision of remembered events gives ''The Glass Menagerie'' its loving, eerie, melancholy resonance."
Tom addresses the audience at the beginning of the play, telling the audience that the play is a memory play, his memory in particular of when he lived in St. Louis with his mother and sister. He also sets the emotional setting of the play by making up aware of his deep sense of guilt and regret at how the relationships he shared with his family were severed.
At other points in the play, Tom turns to the audience and gives us an indication of the mood of the Scene or provides information about how the other characters feel at a given moment in a Scene.