All life is made from CO2 . It was there at earth’s birth, and throughout evolution. It has kept our planet habitable for hundreds of millions of years. It has given us all the splendours of the world we know today. And yet it also holds the potential for life's destruction. In this gripping adventure through eras and places, award-winning science journalist Peter Brannen tells the story of the world’s most important molecule. We travel from the beginning of time all the way up to our present reality, witnessing the staggering journey that CO2 has undertaken. As we watch its movements through the rocks, the air, the oceans and living beings over four billion years, we come to see more clearly what it means for us to be churning through ancient life – in the form of fossil fuels – as we power our industrial world. We are, Brannen shows, performing an unprecedented experiment on our planet. If we are to avoid its catastrophic consequences, we must all begin to deepen our understanding of this curious substance, which has given us everything from the very first life forms on earth to the business titans reshaping our planet today.