Written for plant breeders, researchers and post-graduate students, this book provides a comprehensive review of the methods and underlying theoretical foundations used for selection in plant breeding programmes. The authors review basic elements of population and quantitative genetic theory, and consider in a unique way the tackling of the problems presented by soil heterogeneity and intergenotypic competition when selecting quantitative characters. The efficacy of different methods with regard to developing new varieties of crops are discussed for different modes of reproduction. This work provides a sound basis for informed decision making within the process of a selection programme.