[Sylvia Plath's] is a sensibility disturbed, which sees reflected in the exterior world the very tensions, conflicts, and fears that haunt the inner spirit. Her power as a poet derives from her capacity to express this state of mind through the evocation of profound horror. The sense of horror springs from many sources: from her habit of dredging up historical atrocities, from the violent intensity of her expression, from the accuracy and hardness of her language, and most significantly, from the nature of her perception. Always she is aware of the doubleness of things, the shark beneath the surface, the tumult beneath the calm, the glitter beneath the veil. The gaze which she turns outward upon the world is schizophrenic….

This perception leads first to fear and eventually to despair, for it forces upon one the recognition that the world is disjointed, that things are not what they...