In the 1970s, scientists claimed that farm animal breeding was finally evolving from an art into a science. In their view, the switch to scientific breeding was as inevitable as the ongoing process of agricultural modernization. However, the art-to-science scenario is too simplistic to do justice to the complex dynamic that characterized the transformation of the field. The livestock breeds that take centre stage in this book – dairy cattle, chickens, pigs, sheep, and horses – were products of the twentieth century. The methods used by breeders to improve their animals, however, were much older. Tracing the history of practical stockbreeding, the role of Mendelism in scientific breeding, and the emergence of quantitative genetics, Beauty or Statistics shows that the story of the scientific modernization of livestock breeding can be more fruitfully analysed from the perspective of changing cultures of breeding, taking practical, commercial, normative, and aesthetic considerations into account.