Sherlock Holmes – The world’s first consulting private detective (as he described himself in his initial adventure, A Study in Scarlet). Possessed of a keen intellect and a master of rational, deductive thought (as opposed to giving any credence to superstition or supernatural explanations, as others in The Hound of the Baskervilles do), Holmes may sometimes prove lacking in ordinary interpersonal relationships, but does understand the place and power of human emotions as motivating factors in criminal cases—and manages to maintain a close friendship with his roommate, Dr. John Watson.
Dr. John Watson – A physician who served the British Army in Afghanistan (as established in A Study in Scarlet) but who, at the time of this adventure, is sharing rooms with Holmes at 221B Baker Street, London. (In other Holmes stories, which occur after this one according to internal chronology, Watson has moved out of Baker Street to marry and resume private medical practice.) In The Hound of the Baskervilles, Watson proves his loyalty and utility to Holmes (although the detective seems to grant it slightly begrudgingly) by accompanying Sir Henry Baskerville to his family estate to investigate the death of Sir Henry’s predecessor, Sir Charles.
Sir Henry Baskerville – The young nobleman who has inherited Baskerville Hall following the mysterious death of its former master, Sir Charles. Sir Henry is dedicated to rebuilding both the family manor and the family reputation, and refuses to be scared away from doing so by the legend of a supernatural “hell-hound” that haunts the family in retribution for an ancestor’s long-ago crimes.
Mr. and Mrs. Barrymore – Two long-time personal servants to the Baskerville family, who plan to leave Baskerville Hall once Sir Henry has established himself as lord of the manor. Unbeknownst to anyone, they are giving assistance to Selden, an escaped convict from a nearby prison who is, in fact, Mrs. Barrymore’s brother.
Jack Stapleton – A naturalist with a special interest in catching and collecting butterflies. Stapleton is secretly a member of the Baskerville clan. He is responsible for unleashing his specially bred and phosphorous-decorated hound upon Sir Charles, causing Sir Charles’ death; and is scheming to kill Sir Henry as well when Holmes and Watson become involved in the case. He enlists as his unwilling accomplice his wife, Beryl (Garcia) Stapleton, originally of Costa Rica, whom Jack presents to the world as his sister. Beryl eventually fears for Sir Henry’s life and attempts to warn him of her husband’s plot.
Mrs. Laura Lyons – A young wife who suffers an estranged relationship from her father, the litigious Mr. Frankford, and an abusive relationship with her husband, whom she is attempting to divorce (a bold move for women in Victorian Britain). At the suggestion of Jack Stapleton—she believed him to be single and intending to marry her once her divorce was final—she had made an appointment to meet with Sir Charles the night of his death in order to discuss any financial assistance he might render her; however, she canceled the appointment, again at Jack’s suggestion, unwittingly giving Jack the opportunity to arrange Sir Charles’ murder.