“It was always possible that the Devil was present.” So begins Chris Bohjalian’s “Hour of the Witch” — an historical novel, set in Boston in 1662, that is part thriller and part courtroom drama, leavened with romantic intrigue. For Boston Puritans, the threat of witchcraft is part of everyday life. This prospect will directly complicate the attempt of one young woman, Mary Deerfield, to escape her horrifically abusive marriage. Chris Bohjalian (Courtesy Victoria Blewer) Now 24 years old, Mary has been married to Thomas Deerfield for five years. Two decades her senior, Thomas owns a successful mill in Boston’s North End. He is also a mean drunk who verbally and physically abuses Mary, but who has enough feral cunning to treat her politely when others are around. Mary has also become adept at living a double life: to friends and family, she explains away bruises she can’t hide with tales of clumsiness.