This book describes the methodology for predicting the genetic merit of animals in the context of genetic improvement in an animal breeding programme. Information on an animal and its relatives, on either the characteristic to be improved or from other traits, can be used to predict the animal's genetic merit, taking account of the relationships between measurements and the economic values of traits. The methodology is developed from first principles, without unnecessary detail or complexity, and all the required statistical and mathematical concepts are fully described in the book. The text discusses the methods for combing different sources of information and illustrates their use with examples of breeding programmes in cattle, sheep, pigs and poultry. A series of questions with detailed answers is included in the book, to help reinforce the ideas and provide some practical experience in the prediction of genetic merit. The text is aimed at final year undergraduate and first year postgraduate students of quantitative genetics and animal breeding.