Adam Trask is the older half-brother of Charles Trask, the father of Caleb and Aron Trask, and the son of Cyrus Trask. He mirrors the biblical Adam in many obvious ways. He shares a name with Adam and is known for his sweet disposition, just like the biblical Adam. Adam Trask is seduced and nearly defeated by a driven woman, just as Adam was seduced into falling into sin by following Eve.

Adam’s flaws are also his best qualities. He’s kind to others, wishes no one ill will, and acts as a godlike figure to Cal and Aron. Although this gives him a reputation for being nice, he’s also foolish, easily manipulated, and forced into situations he doesn’t want. Adam’s badness is his arbitrary preference for Aron over Cal. At the end of the story, Adam dies but gives his son Cal his blessing (and breaks the Trask family curse) before passing on.

Adam’s younger half-brother, Charles Trask, is the first character Steinbeck uses to question beliefs about good and evil. Charles can’t control his anger, but that bad quality doesn’t make him a bad person. He’s capable of killing in a fit of anger, and he sleeps with his brother’s wife.