The Bell Jar is a glass jar used to protect things of value; Sylvia Plath uses this imagery throughout the book to show Ester's isolation. Esther has her own "Bell Jar," because she feels isolated all the time, depressed for no reason, and is completely and utterly confused about her future. This idea complete isolation and depression for no reason is a problem because Esther is supposed to be having the time of her life, yet she seems too entrapped in her own bell jar, thus isolating her and keeping her from having fun or enjoying anything. All these things enviably led to her physiological breakdown.

To begin, Esther feels isolated from everyone all the time. She never seems to fit in or want to. One prime example of this is when she is in New York and supposed to be having the time of her life; she...