Volume 1: A Study in Scarlet 

One of the four novels within the sixty episodes of the Sherlock Holmes canon, A Study in Scarlet(1877) marked the debut of Holmes and his assistant, Dr. Watson, along with their residence at 221 B Baker Street, Inspector Lestrade, and the ragtag band of street urchins Holmes referred to as "the Baker Street Irregulars." Doyle modeled Holmes in part upon the idiosyncrasies of one of his medical school instructors, Dr. Joseph Bell; the literary structure, however, he borrowed from Edgar Allan Poe's stories of Auguste Dupin. The brilliant but eccentric detective, the admiring friend who narrates the story, the cases which are puzzling and fantastic as much as sensationally criminal, the dramatically revealed solution at the end; all these are elaborated from Poe's work