An astonishing exploration of planet formation and the origins of life by one of the world's most innovative planetary geologists. In 1959, the Soviet probe Luna 3 took the first photos of the far side of the moon. Even in their poor resolution, the images stunned scientists: the far side is an enormous mountainous expanse, not the vast lava-plains seen from Earth. Subsequent missions have confirmed this in much greater detail. How could this be,...