This book mainly focuses on the worth of production of single cross hybrids in Maize. Maize (Zea mays L.; 2N=20) is an important cereal crop belonging to the tribe Maydeae, of the grass family, Poaceae. It is used world-wide for feed, food and also serves as a source of basic raw material for a number of industries viz., starch, protein, oil, alcoholic beverages, food, sweeteners, cosmetics, bio- fuels etc.Hybrid is one of the greatest practical contribution of genetics and has its most significant expression in maize crop. Single cross hybrids are expected to be extremely uniform with greater yield potential, good seed quality and better stability of performance. Information on combining ability provides guidelines to the plant breeder in selecting the elite parents and desirable cross combinations to be used in the formulation of systematic breeding programme and at the same time reveals the nature of gene action involved in the inheritance of various traits and there by breeding methodology to be used. In the view of above facts, the present book was written.