Robert Louis Stevenson (1850-94), celebrated author of Treasure Island  (1882-3), Kidnapped (1886), and "The Strange Case of Dr. Jekyll and Mr. Hyde" (1886) was a lifelong connoisseur of "penny dreadfuls": illustrated serial fiction that targeted working-class readers. In Stevenson's childhood, his nurse Alison Cunningham often read dreadfuls to him. In adulthood, he was haunted by one dreadful in particular. This was A Mystery in Scarlet by “Malcolm J.