The Bell Jar is based largely on Plath's own suicide attempt (summer, 1953) and subsequent treatment at McLean Hospital in Belmont, Massachusetts. The novel represents a culmination of Plath's attempts to describe her experience of mental illness and treatment.
In writing the book, mainly in 1961, Plath reused a number of phrases from earlier poems, including the description of electroshock therapy, "darkness wipes me out like chalk on a blackboard" (from "Face Lift"). The Bell Jar launched the final phase of Plath's career; she wrote some of the poems later published in Ariel, the book which secured her place in the canon, on the back of Bell Jar drafts.