Lovelace is best known for her books for children. The Betsy-Tacy series started in 1938 after Lovelace told stories about her childhood to her own daughter, Merian. The character Betsy is based on Lovelace herself; Tacy is based on her childhood best friend, Frances "Bick" Kenney. The first book in the series, "Betsy-Tacy", was published in 1940, and the last book, "Betsy's Wedding", was published in 1955. The first four books increase in reading difficulty so that the child can grow up along with Betsy-Tacy. The Betsy-Tacy books take place mostly in the fictional town of Deep Valley, Minnesota, which is based on Mankato. They cover the period from the late 1890s, when Betsy is five years old, until World War One, by which time Betsy is newly married and has recently completed a grand tour of Europe.