Earth has existed for an immense period of time—an almost unimaginable 4.6 billion years. If we ventured far enough into the past, would we reach a time when our planet was fundamentally different? Did it always have landscapes like those we see today, sculpted by wind, rain, and the forces of plate tectonics? When did Earth turn into the distinctive “blue planet” where life could emerge and evolve?

Geologist Simon Lamb shows that the key to answering these questions lies in ancient rocks from the days when the planet was young. His research in remote southern Africa looks at some of the oldest known rocks—some more than 3.5 billion years old—which have survived unfathomable spans of geological time. He takes readers on a journey of scientific discovery, walking—and sometimes diving—through landscapes from the time of the earliest known forms of life. Lamb unearths a violent world of natural disasters and climate change in the deep ocean, along ancient shorelines, and amid rising mountains. In so doing, he shows how geologists work and think, and how they read rocks and decipher what they tell us of the past. Finding the foundations of our world, The Oldest Rocks on Earth sheds light on why Earth is the only planet known to harbor life and what this might tell us about our future.