What can a fingernail tell us about the mysteries of creation? In one sense, a nail is merely a hunk of mute matter, yet in another, it’s an information superhighway quite literally at our fingertips. Every moment, streams of molecular signals direct our cells to move, flatten, swell, shrink, divide, or die. Andreas Wagner’s ambitious new book explores this hidden web of unimaginably complex interactions in every living being. In the process, he unveils a host of paradoxes underpinning our understanding of modern biology, contradictions he considers gatekeepers at the frontiers of knowledge.