The new American Girl on the block is Josefina Montoya, a Mexican girl living on a rancho near Santa Fe in 1824. Josefina's mother has died, and she and her three sisters are struggling to help their father run the rancho without her. The arrival of their aunt from Mexico City brings new affection into their lives, and, for Josefina, the special gift of music, for T°a Dolores has brought along her piano. This well-researched novel includes the usual ``Peek into the Past'' section that provides a historical context for the story, as well as a glossary of Spanish words. Tripp writes in an undemanding style, with a less dynamic heroine, and a more predictable plot than other titles in the series; still, a familiar format and readers' brand loyalty mean this book will find a ready and eager audience. (Fiction. 7-10)