 Brilliant Sordio presents the unabridged recording of Endless Forms Most Beautiful, the new science of Ivo-Divo and the making of The Animal Kingdom by Sean B. Carroll, performed by Arthur Murray. For Jamie, Will, Patrick, Chris, and Josh, Preface, Revolution Number 3 The physicist and Nobel laureate Jean Perrin once stated that the key to any scientific advance is to be able to explain the complex visible by some simple invisible. The two greatest revolutions in biology, those in evolution and genetics, were driven by such insights. Darwin explained the parade of species in the fossil record and the diversity of living organisms as products of natural selection over eons of time. Molecular biology explained how the basis of heredity in all species is encoded in molecules of DNA made of just four basic constituents. As powerful as these insights were, in terms of explaining the origin of complex visible forms from the bodies of ancient trilobites to the beaks of Galapagos finches, they were incomplete. Neither natural selection nor DNA directly explains how the individual forms are made or how they evolved. The key to understanding form is development, the process through which a single-celled egg gives rise to a complex, multi-billion-celled animal. This amazing spectacle stood as one of the great unsolved mysteries of biology for nearly two centuries, and development is intimately connected to evolution because it is through changes in embryos that changes in form arise. Over the past two decades, a new revolution has unfolded in biology. Advances in developmental biology and evolutionary developmental biology, dubbed evo-devo, have revealed a great deal about the invisible genes and some simple rules that shape animal form and evolution. Much of what we have learned has been so stunning and unexpected that it has profoundly reshaped our picture of how evolution works. Not a single biologist, for example, ever anticipated that the same genes that control the making of an insect's body and organs also control the making of our bodies. This book tells the story of this new revolution and its insights into how the animal kingdom has evolved. My goal is to reveal a vivid picture of the process of making animals and how various kinds of changes in that process have molded the different kinds of animals we know today and those from the fossil re-