A handful of discoveries have changed the course of human history. This book is about the most recent and potentially the most powerful and dangerous of them all. It is an invention that allows us to rewrite the genetic code that shapes and controls all living beings with astonishing accuracy and ease. Thanks to it, the dreams of genetic manipulation have become a stark reality: the power to cure disease and alleviate suffering, to create new sources of food and energy, as well as to re-design any species, including humans, for our own ends. Jennifer Doudna is the co-inventor of this technology - known as CRISPR - and a scientist of worldwide renown. Writing with fellow researcher Samuel Sternberg, here she provides the definitive account of her discovery, explaining how this wondrous invention works and what it is capable of. She also asks us to consider what our new-found power means: how do we enjoy its unprecedented benefits while avoiding its equally unprecedented dangers? The future of humankind – and of all life on Earth – is at stake. This book is an essential guide to the path that now lies ahead.