A prominent, popular London scientist, who is well known for his dinner parties, Jekyll is a large, handsome man of perhaps fifty. He owns a large estate and has recently drawn up his will, leaving his immense fortune to a man whom Jekyll's lawyer, Utterson, thoroughly disapproves of.
Jekyll's own story of his life is recorded in his "Statement," which comprises the entirety of Chapter 10.
He was born to a good family, had a good education, and was respected by all who knew him. As a youth, he thinks that perhaps he was too light-hearted. He confesses to many youthful indiscretions, which he says that he enjoyed very much — indiscretions which he was very careful to keep secret. However, there came a time when he realized that his professional career could be ruined if one of these indiscretions were to be exposed, and so he repressed them.
Now, however, that he is middle-aged, he has been fascinated with the theory that man has a "good" side and a "bad" side, and he has decided to investigate the theory. His investigations were successful; he compounded a potion that could release the "evil" in a person in the form of an entirely different physical person, one who would take over one's own body and soul. Then one could commit acts of evil and feel no guilt; furthermore, one could drink the same potion and be transformed back into one's original self.
Jekyll's evil dimension took the form of Edward Hyde, a man who committed any number of crimes and performed acts of sexual perversion; seemingly, his most serious crime is the vicious murder of Sir Danvers Carew, a Member of Parliament.
Jekyll's fascination with his "other" self became so obsessive that he was finally no longer able to control the metamorphosis process, and Edward Hyde began appearing whenever he wanted to — and not at the command of Dr. Jekyll. Jekyll became, therefore, a frightened recluse, trying desperately to control Hyde, but successively failing, especially whenever he would doze off. Finally, crazed by anxiety and a lack of sleep, he hears Utterson and Poole, his butler, breaking down his private study door and, in desperation, he commits suicide, but just as he loses consciousness, Hyde appears, and it is the writhing body of the dying Hyde which Utterson and Poole discover.