Wikipedia
The 'Betsy-Tacy 'books are a series of semi-autobiographical novels by American novelist and short-story writer Maud Hart Lovelace (1892-1980), which were originally published between 1940 and 1955 by the Thomas Y. Crowell Co. The books are now published by HarperCollins. The first four books were illustrated by Lois Lenski and the remainder by Vera Neville.
The series follows the adventures of heroine Betsy Ray, who is based closely on the author, and her friends and family. The first book, Betsy-Tacy, begins in 1897 on the eve of Betsy's fifth birthday, and the last book, Betsy's Wedding, ends in 1917 as the United States prepares to enter the First World War.
Betsy-Tacy (1940) is the first volume in the Betsy-Tacy series by Maud Hart Lovelace.
The book is mostly about the adventures of five-year-old Betsy Ray and her new best friend, Tacy Kelly. It takes place in the fictional Deep Valley, Minnesota- based on Mankato, Minnesota, the author's home town. This first book is set in roughly 1898-1899.