The Betsy-Tacy Series is a collection of children's books written by author Maud Hart Lovelace. The series follows the adventures of two young girls, Betsy Ray and Tacy Kelly, growing up in the early 1900s in the fictional town of Deep Valley, Minnesota. The stories capture their friendship, family life, and experiences as they navigate childhood and adolescence. The series consists of several books, starting with "Betsy-Tacy," published in 1940. It has been praised for its relatable characters and vivid depiction of everyday life during that era. The books are cherished for their warmth, humor, and timeless themes of friendship and growing up.