O Pioneers! is a 1913 novel by American author Willa Cather, written while she was living in New York. It is the first novel of her Great Plains trilogy, followed by The Song of the Lark (1915) and My Ántonia (1918).

Part I – The Wild Land

On a windy January day in Hanover, Nebraska, Alexandra Bergson is with her five-year-old brother Emil, whose little kitten has climbed a telegraph pole and is afraid to come down. Alexandra asks her neighbor and friend Carl Linstrum to retrieve the kitten. Later, Alexandra finds Emil in the general store with Marie Tovesky. They are playing with the kitten. Marie lives in Omaha and is visiting her uncle Joe Tovesky.

Alexandra's father is dying, and it is his wish that she run the farm after he is gone. Alexandra and her brothers Oscar and Lou later visit Ivar, known as Crazy Ivar because of his unorthodox views. For instance, he sleeps in a hammock, believes in killing no living thing and goes barefoot summer and winter. But he is known for healing sick animals. Alexandra is concerned about their hogs as the hogs of many of their neighbors are dying.