Stevenson was born in Edinburgh in 1850. He was sickly as a child and adult which meant he was familiar with medical practices. He trained in the law, which is Utterson’s profession.

In the 1900s, London was a city of extremes of wealth and poverty, with a lot of violent crime. It was plagued by thick fogs.

Advances in science in the nineteenth century changed the way people saw the world and humanity. Psychology – the science of the mind – was just beginning.

Many people became interested in the paranormal and spirits in the nineteenth century. Some, like Lanyon, thought it all nonsense. Others remained undecided.

Gothic literature was popular from the eighteenth century. It told supernatural tales of horror and madness, using mysterious settings and exploring strange and fearful ideas.