Sean Carroll explores how evolution has shaped nature's wondrous complexity and diversity, from insects to octopuses, from mice to men. We not only share nearly 99% of our genes with chimps, we also have some 35% in common with daffodils. Throughout much of the animal and even plant kingdoms, almost the same ancient genes code for almost the same proteins. And further, to everyone's astonishment, the genes involved in making the complex eyes of fruitflies are close matches to those involved in making the very different eyes of octopuses and people. So what leads to the nature's 'endless forms most beautiful'? The key to this mystery is being unravelled by 'Evo Devo' or the new science of evolutionary development biology. By looking at how a single-celled egg gives rise to a complex, multi-billion celled animal, Evo Devo is illuminating exactly how new species - butterflies and zebras, trilobites and dinosaurs, apes and humans - are made and evolved. The key, it turns out, is all about location and timing. For anyone who has ever pondered 'where did I come from', Endless Forms Most Beautiful explores our history, both the journey we have all made from egg to adult, and the long trek from the origin of life to the very recent origin of our species.