East of Eden begins with the narrator’s description of the Salinas Valley in California, where the story unfolds. The next chapter introduces the Hamilton family, beginning with the narrator’s grandfather Samuel Hamilton, who during the 1860s came to California from Ireland with his wife Liza.
The focus then switches to the Trask family, living on a farm in Connecticut. Cyrus Trask is a Civil War veteran who becomes a powerful man in the War Department in Washington, D.C. Trask has two sons, Adam and Charles. During their boyhood, Cyrus rejects a birthday present from Charles but accepts the present given by Adam. This angers Charles, and he beats Adam severely. Cyrus forces Adam to join the army.
The narrative then switches to the Hamilton family, which is thriving, even though Samuel never makes much money. Samuel’s four sons, George, Will, Tom, and Joe, are born.