Not since the atomic bomb has a technology so alarmed its inventors that they warned the world about its use. Not, that is, until 2015, when biologist Jennifer Doudna called for a worldwide moratorium on the use of the gene-editing tool CRISPR - a revolutionary new technology that she helped create - to make heritable changes in human embryos. The cheapest, simplest, most effective way of manipulating DNA ever known, CRISPR may well give us the cure to HIV, genetic diseases, and some cancers. Yet even the tiniest changes to DNA could have myriad, unforeseeable consequences - to say nothing of the implications of intentionally mutating embryos to create "better" humans. Writing with fellow researcher Sam Sternberg, Doudna shares the thrilling story of her discovery and describes the enormous responsibility that comes with the power to rewrite the code of life. Two scientists explore the potential of a revolutionary genetics technology capable of easily and affordably manipulating DNA in human embryos to prevent specific diseases, addressing key concerns about related ethical and societal repercussions.

Prologue: the wave -- Part I. The tool -- The quest for a cure -- A new defense -- Cracking the code -- Command and control -- Part II. The task -- The CRISPR menagerie -- To heal the sick -- The reckoning -- What lies ahead -- Epilogue: the beginning.