The book was semi-autobiographical of Plath's life. To protect herself and the charachters based on real people, she first published the book under the name Victoria Lucas. It wasn't published under her real name until 1971, 9 years after Plath's suicide in 1963.
(Spoilers ahead.)The book follows Esther Greenwood (The main charachter who Plath based herself on) who although is a striving young writer, finds herself spiraling downward into depression and eventually a suicide attempt. She eventually is put into a mental institution. Esther is given electroshock therapy, which, along with therapy helps to her to regain her sanity and cure her depression, which she describes in a most beautifully sad way, as being "trapped under a bell jar, stewing in her own sour air" (Spoilers end.)
The book's portrayal of coping with and overcoming depression has made it a classic that many women can relate to.
(Esther is about to leave the asylum, and her doctor has told her to think of her past as 'a bad dream')
-"A bad dream.
To the person in the bell jar, blank and stopped as a dead baby, the world itself is the bad dream.
A bad dream.
I remembered everything."-