Animal breeding is a branch of animal science that addresses the evaluation of the genetic value of domestic livestock. Selecting animals for breeding with superior the genetic value in growth rate, egg, meat, milk, or wool production, or have other desirable traits has revolutionized agricultural livestock production throughout the world. This handbook include scientific theory of animal breeding; population genetics, quantitative genetics, statistics, and molecular genomics. The Applied Animal Breeding and Genetics handbook provides knowledge on the role and sustainable use of genetic variation in animals by providing knowledge to support the adequate supply of safe and healthy food of animal origin, and to enhance welfare and productivity of animals. The handbook combines quantitative and molecular genetics related to the biological functioning of animals. Also, describe genetic variation in farm and companion animals, and examines opportunities to use naturally occurring genetic variation in selection schemes.