Emily Jane Brontë was born 30 July 1818, fifth (and oddest1) child of Patrick and Maria Brontë. Maria died when Emily was only three, but, like her sister Charlotte, Emily was later prone to creating motherless characters. She got along best with Anne, the youngest, and they created the world of Gondal together2. At 17, Emily went to the Roe Head School (her first experience with school since a very brief stint at the infamous Clergy Daughters' School) where Charlotte was then teaching. Emily managed to stay only three months before her nerves became too frazzled and she had to go home. She simply couldn't stand not being able to write and think about Gondal as much as she wanted to3.
Emily found a teaching job at Law Hill School in September 1838. The hours were grueling: 6 AM to 11 PM, with half an hour's break, and though Emily managed to do all right in her first term4, her health broke under the stress and she returned home around April 1839. She never again attempted to find any kind of a job.
In 1842, Charlotte dragged Emily to a school in Brussels5. Emily did well (her teachers were especially impressed with her clear, smooth writing style) but made no friends, as was typical for her. She went back home as soon as she possibly could.
Emily had been writing poetry all this time, mostly on Gondal, and in the autumn of 1845, Charlotte found these poems and read them. She then approached her sister and urged her to publish the works. Emily was furious, and Anne interceded, giving her own Gondal poems to Charlotte to help make peace. After editing the poems to remove some of the Gondal-ness, Emily agreed to the publication of Poems under the Acton, Ellis, and Currer Bell pseudonyms6.
In 1846, about the time Charlotte finished The Professor, Emily finished Wuthering Heights. Its style is pure Gondal, and it was almost universally condemned as being far too shocking for anyone to read7. It was this which kept most people thinking of the authors of these books as men, believing that no woman could write such things, even when rumors that they were women started circulating.
Branwell died in September 1848, and Charlotte succumbed to her usual psychosomatic illnesses, not realizing that Emily was in fact truly ill. By October, the decline in Emily's health was obvious, though she frustrated the entire family by her refusal to answer any questions or take any advice about her health. Though it was clear she had consumption, she grew angry at even the suggestion of doctors or medicine. On 19 December 1848 she finally collapsed, saying, "If you will send for a doctor, I will see him now." She died early that afternoon, aged thirty.
Charlotte called her sister a "baby god," and always mourned the loss of what Emily might have written had she lived. There is a chance that Charlotte did in fact destroy an uncompleted second novel of Emily's, perhaps feeling that the subject of the novel might do harm to Emily's reputation, of which Charlotte was extremely protective. Charlotte always felt that there were certain subjects which should not be handled in novels, and it's possible that Emily had started working with one of those subjects, causing Charlotte to fear even nastier reviews than the ones for Wuthering Heights. In my opinion, Charlotte should've minded her own business.
Barker, Juliet. The Brontës. New York: St. Martin's Press, 1994.