The Bell Jar is the matrix of Sylvia Plath's work and anticipates her transition into neurotic writing. Indeed, her task of correcting the proofs of this novel may well have determined the direction as well as the energy of the late poems. In particular, the verbal parallels between The Bell Jar and "Daddy" are numerous and striking.

    My German-speaking father, dead since I was nine, came from some manic-depressive hamlet in the black heart of Prussia.
      There's a stake in your fat, black heart …
    What I didn't say was that each time I picked up a German dictionary or a German book, the very sight of those dense, black, barbed-wire letters made my mind shut like a clam.
                I never could talk to you.
                The tongue stuck in my jaw,
                It stuck in a barb wire snare.
                                                (p. 605)

The poem says (echoing The Bell Jar) that her father...