Almost every trait in nature shows variation, both within populations and between populations and species. The field of quantitative genetics is the very broad umbrella that attempts to separate environmental from genetic sources of variation. As a result, it has powerful applications in animal and plant breeding, evolution, ecology, medicine, anthropology, behaviour, population genetics, conservation biology, genomics, and statistics.This second edition of Genetics and Analysis of Quantitative Traits is a fully rewritten and greatly expanded revision of the first edition, published in 1998, which provided the first, modern, unified treatment of quantitative genetics. In the past two decades, there have been massive advancements in the field coupled with explosive growth in new quantitative methods; those developments are covered in this new edition.The book weaves important biological applications with a full development of the theory and appropriate statistical tools. There are extensive discussions of important linear-algebra tools, linear and mixed models, likelihood and Bayesian estimation, as well as false discovery rates, multiple comparisons, and meta-analysis. More than 100 worked examples (ranging from microbes to humans) illustrate the key concepts using real-world applications.This extensive reference will be suitable for graduate-level students and professional researchers (both empiricists and theoreticians) in the fields of evolutionary biology, genetics, and genomics. It will also be of particular relevance and use to applied evolutionary biologists working in breed improvement for agriculture, human geneticists, and statisticians.