Darwin's theory of natural selection was a monumental step in our understanding of evolution, explaining how useful adaptations are preserved over generations. However, Darwin's great idea didn't - and couldn't - tell us how those adaptations arise in the first place. On its own, can random mutation really be responsible for all the creative marvels in nature? Renowned evolutionary biologist Andreas Wagner presents the missing piece of Darwin's theory. Using cutting-edge experimental technologies, he has found that adaptations are driven by a set of laws which allow nature to discover new molecules and mechanisms in a fraction of the time that random variation would take. Meticulously researched, carefully argued, and full of fascinating examples from the animal kingdom, Arrival of the Fittest signals an end to the mystery of life's rich diversity.