There were lots of children on Hill Street, but there were no little girls Betsy's age. So when a family moved into the house across the street, Betsy hoped they would have a little girl she could play with. Sure enough, they did. The girl's name was Tacy, and after a while she and Betsy became such good friends that everybody thought of them as one person - Betsy-Tacy.

Betsy-Tacy did all kinds of things. They made a playhouse from a piano box. They went to their first day of school together and even sat in the same seat. They rode in the milkman's wagon. And Betsy made up wonderful stories that they kept as their own special secrets. Then they met Tib, who came to share in their games.

Ever since their first publication in the 1940s, the Betsy-Tacy stories have been loved by each generation of young readers.