It sounds as if animal breeding is all in the hands of the humans. Compared to natural populations this indeed is the case, as we decide which animals are allowed offspring and which are not: selective breeding or in other words. However, as in natural artificial selection populations there is another force that plays an important role and that is the force of natural. In natural selection it is not us but the environment that determines survival and selection reproductive success of animals. The application of scientific methods to animal breeding has led to major improvements in the output, cost and quality of meat, milk and fibre. In addition, animal breeding plans are important for continued improvement of companion animals and management of endangered species. This book describes the methodology for predicting the genetic merit of animals in the context of improvement in an animal program. This well organized and readable book is a must have resource guide for all biotechnology and veterinary science students and researchers.