Dr Jekyll and Mr Hyde is one of the great thrillers of world literature. As in traditional thrillers, the various elements that make up the plot are pulled together ,in the end ,by one of the characters - in this case two, Dr Lanyon and Dr Jekyll, for the final explanation of the mystery. Other elements of the crime story are: the title, which points to "police case" and "medical, psychological case", the setting in a foggy and bad lit London, of deserted streets, with most scenes taking place during the night; the scattered cues which may lead to the solution of the case: the fact, for example, that the door from which Hyde has been seen coming out is the back door to Jekyll’s laboratory.This thriller deals with some of the most relevant issues for modern man at an ethical level, in fact it brings forth the problem of evil within man in a way that both shocked and immensely pleased contemporary readers.

Dr Jekyll, a highly-reputed scientist who leads a quiet and sober life, is obsessed with the idea that his evil tendencies - which are in fact quite normal and representative of the average man - can be separated from his good side, giving birth to two beings: one wholly good and one wholly bad.Discovering a drug that works this change, he takes it and finds that it turns him into a new person, physically deformed and of an evil nature; this ugly man, who commits all sorts of crimes, is called Mr Hyde. When Jekyll wants to return to his usual self all he has to do is to take the drug again.However, fearing that for some reason he might remain trapped within the body of Hyde, he gives instructions for his house and servants to be at Hyde’s disposal, opens a bank account in Hyde’s name, and even makes him his sole heir in his will. This particularly worries his friend and lawyer, Mr Hutterson, who tries to discover more about Hyde and the reason why Jekyll protects him.With time, Hyde’s evil nature grows, to the point that he commits murder and is ready to do more. Jekyll is frightened by this and would like to ger rid of Hyde forever, but he finds that he has lost control over him; it is Hyde, in fact, who takes over Jekyll’s body without needing the drug anymore. Seeing he has no way out of this situation, Jekyll closes himself in his laboratory and commits suicide, leaving a long note in which he explains his case.