Mary Shelley was born Mary Wollstonecraft Godwin on August 30, 1797 in London, England. Her mother was Mary Wollstonecraft, a famous feminist, and her father, William Godwin, was an anarchist and atheist philosopher. Her mother died only ten days after her birth, but her father remarried.

As a youth, Mary was home-schooled by her father, who gave her an outstanding education on a variety of subjects. She also met Percy Bysshe Shelley, a friend of her father, who was also a radical philosopher and the two fell in love. In the summer of 1814, they went on a trip to France, but her father disowned her afterward.

Percy took over tutoring Mary, but he also tried to instill his beliefs of free love into her. He told her that she should share herself with his friend Thomas Hogg as sort of a love triangle, but she refused to participate in that type of relationship. The couple spent much of their time reading classic novels and poetry.

In May of 1816, they went to stay in Lake Geneva and visit Lord Byron, a fellow writer. Percy began writing some new material and Mary began to think about writing her own novel. One day they decided to have a contest to see who could write the best ghost/horror story.

Mary was initially uninspired and couldn't come up with an idea. She went to sleep that evening and had a dream where she saw "the pale student of unhallowed arts kneeling beside the thing he had put together". She used this dream as the inspiration for a novel that would become "Frankenstein".

Percy and Mary returned to England in September of 1816. On October 9, 1816, Mary's half sister committed suicide at a nearby inn. On December 10, 1816, Percy's first wife drowned herself in Hyde Park. Percy had offered to let her live at their home with Mary, but she had refused and could not cure her depression.

After the death of his first wife, Percy asked Mary to marry him and she accepted. They were able to reconcile with Mary's father, who gave their marriage his blessing. The couple had three children, but two of them tragically died, leaving them with only a single son, Percy Florence Shelley.

In 1817, Mary finished "Frankenstein" and published the novel. It became a massive success and is still read by many today, nearly 200 years later. The story also spawned numerous films, including Jimmy Whale's famous treatment.

The family then moved to Lerici in Italy, where Mary nearly died from a miscarriage. In July of 1822, her husband Percy went sailing up the Italian coast, but was caught in a storm and died at sea on July 8, 1822. Mary continued to publish his work after his death and also worked on more of her own novels. However, none of her new novels were able to rival the success of her first work, "Frankenstein".

One of Mary's last works was 1819's "Matilda", a story that was not published until 1959. The story was about a case of father and daughter incest and her father refused to allow it to be published. Some theorize that he was involved with an incestuous relationship with her during her youth.

On February 1, 1851, she died from brain cancer in the city of London. She was buried in St. Peter's Churchyard in Bournemouth, England.