[What] Letters Home reveals, is that the various roles Plath assumed—Dutiful Daughter, Bright and Bouncy Smith Girl, Cambridge Intellectual, Adoring Wife and Mother, Efficient Housekeeper—were so deeply entrenched that they determined the course not only of her life but also of her writing. If, as Karl Miller so rightly observes, Plath's letters to her mother were "bent on withholding her 'true' condition," so, the correspondence suggests, were the poems written prior to the final crisis in her life, poems that emerged, in large part, from Plath's false-self system. (p. 156)

In coming to terms with the transformation of "Sivvy," the carefully controlled voice of the earlier poetry and prose, into the Sylvia of the Ariel poems …, Letters Home is a centrally important document…. [Despite] the fractured state of the final manuscript, the portrait of Sylvia that emerges is peculiarly consistent.

One learns, to begin with, that Sylvia...