Who was the subject of the book?

The book's narrator, Jim Burden, arrives in the town of Black Hawk, Nebraska, on the same train as the Shimerdas, when he goes to live with his grandparents after his parents have died. Jim develops strong feelings for Ántonia, something between a crush and a filial bond, and the reader views Ántonia's life, including its attendant struggles and triumphs, through that lens.