The Eye of the Beholder — Marc Behm

Eye of the Beholder is a cult classic that inspired both French and English film adaptations. Joanne Eris has a bad habit of marrying men that wind up dead. An unnamed private detective, simply known as "The Eye" is hired to investigate the death of her husband. The novel charts the development of the detective's dangerous obsession with a femme fatale, as he pursues her across the United States.