"Teacher seeks pupil. Must have an earnest desire to save the world." The nameless narrator, cynical about the ad after his own disillusioning brush with 1960s idealism, tracks down its author anyway — and finds Ishmael, a gorilla who communicates telepathically. Captured from the wild decades earlier and eventually able to converse with a zoo owner's family, Ishmael has spent years developing a philosophy of human civilization and now seeks a student to carry it forward.
Through Socratic dialogue, Ishmael divides humanity into "Takers" — the dominant culture that believes itself destined to rule and endlessly expand — and "Leavers," tribal peoples who live within natural limits. Daniel Quinn's novel uses this framework to mount a sweeping critique of agriculture, progress, and the myths a civilization tells itself to justify consuming the world it depends on.