While Sherlock Holmes pooh-poohed the notion that the supernatural could invade our daily lives, not all fictional detectives have. There is a long history of literary sleuths who accept the reality of those supernatural intrusions in order to solve a case-be it a haunting or a crime. There are also characters who rely on their own supernatural abilities in their battle against lawbreakers. These are the occult detectives. Bram Stoker's Dr. Van Helsing,...