Four and a half billion years ago, the young earth was a hellish place—a seething chaos of meteorite impacts, volcanoes belching noxious gases and lightning flashing through a thin, torrid atmosphere. With no protective ozone layer, ultraviolet radiation sterilized Earth’s hot, bleak surface. Then, in a process that has puzzled geologists and biologists alike for decades, the first microbes took hold. How did it happen? In Life’s Rocky Start, dynamic geophysicist Robert Hazen advances a startling and counterintuitive idea—that the rocks beneath our feet were essential to jump-starting life. As Hazen sets out on a journey of scientific discovery to spectacular locations from Hawaii to Australia to Morocco, we discover that as microbes flourished and took over the biosphere, hundreds of minerals we know and depend on today were born. In a grand adventure through billions of years of history, the story of life on Earth is revealed as fundamentally interwoven with the epic, unfolding story of Earth itself.