Elizabeth George Speare was born in 1908 and died in 1994. A novelist best known for her historical fiction, Speare won two Newberry awards for children's literature. Published in 1958, The Witch of Blackbird Pond was Speare's second historical novel and her first Newberry Award winning book. After earning a master's degree in English literature from Boston University, Elizabeth met and married her husband. The two settled down in Connecticut. Most of Speare's novels were set in New England, where the geography was familiar, however she frequently did research to provide the setting for her novels.
The Witch of Blackbird Pond is set in and around Wethersfield, Connecticut: a town in Hartford County on the Connecticut River. The town really was founded by Puritans, who really were a group of religious radicals expelled from England and Holland due to their rather obnoxious habit of forcing their religious opinions and preferences onto others. In the mid-1600s, four people really were tried for witchcraft and convicted, although the last person to be so convicted had her sentenced reversed; since she was guilty only of being a female landowner she was banished and her property was confiscated by her neighbors. Modern historians debate how seriously the townspeople actually believed in witchcraft, or whether the accusation of witchcraft was merely a ploy to gain control of the accused person's property or to dispose of a social or business rival.
A few of the minor characters in The Witch of Blackbird Pond were real people: Dr. Gersholm Bulkeley the minister, Eleazer Kimberly the schoolteacher, Governor Edmund Andros, and the magistrate Captain Samuel Talcott. All the other characters are fictional.
Speare's historical novels are somewhat sanitized for child audiences. In Barbados, for example, Kit is described as having had "servants". In reality, a young woman of privilege growing up in Barbados would have had slaves, not servants. However presenting Kit as a former slave owner would have made her into less of a compelling protagonist particularly given the nascent civil rights movement which was gathering momentum in the United States in the 1950s when The Witch of Blackbird Pond was written and published.
Plot-wise, The Witch of Blackbird Pond is a fish-out-of-water novel. No matter how she tries, Kit simply doesn't fit in. The harder she tries to help people, the more she alienates them. Not only will she never be happy or comfortable with the hard work and simple pleasures of Puritan life, but her habits, personality, and mannerisms make the other townspeople genuinely uncomfortable. Indeed, making her own circle of friends among her fellow outcasts only creates more trouble for Kit and the other outcasts.
Despite her unusual habits, Kit's sincerity and personality do win people over. Her aunt, uncle, and cousins come to care for her, as do several of her fellow outcasts, including a child whom she teaches to read. The technique Kit uses to teach Prudence to read and write -- copying letters such as the letters of her own name -- is still in use in classrooms today.