From About the Author in the Great Illustrated Classics version of The Strange Case of Dr. Jekyll and Mr. Hyde:

Robert Louis Stevenson was born in Edinburgh, Scotland, in 1850.  He was a frail child, who was greatly influenced by his father's punishments and by his nurse's horrifying tales of demons.  Stevenson refused to follow the family profession of engineering and chose law when he went to the University of Edinburgh to study.  But he soon gave that up and turned to writing, which his poor health could not deter.  After he married an American woman, Stevenson and his devoted wife traveled throughout the world trying to improve his delicate health while he continued his writing.  In the four years between 1883 and 1887, Stevenson wrote his four longest and greatest novels: Treasure Island, The Black Arrow, The Strange Case of Dr. Jekyll and Mr. Hyde, and Kidnapped, and his famous book of poems, A Child's Garden of Verses.

The Strange Case of Dr. Jekyll and Mr. Hyde was born in a nightmare, but Stevenson remembered enough of it when he awoke to get it down on paper.  Within three days he had the entire first draft written.  He intended this book not only as a "thriller," but also as a study of good and evil, which are always at war within man.

Stevenson and his family spent his last years on the South Pacific island of Samoa, where he continued his writing until he collapsed and died in 1894... at the young age of forty-four.