Sustainable crop production is one of the most serious challenges facing humankind. Increasing the efficiency with which crops utilise mineral nutrients is fundamental to sustainable crop production. This book brings together knowledge in agronomy, plant physiology, molecular biology and genetics to identify strategies to improve crop nutrient use efficiencies. It is a book primarily for researchers and university students, written by experts in their fields. The book begins with an overview of the definitions of nutrient use efficiency and plant traits that might increase crop yields while reducing fertilizer inputs. Several chapters then provide more details of root and shoot traits required to improve the acquisition and physiological utilisation of mineral nutrients, in particular nitrogen and phosphorus, for greater crop yields and quality. The following chapters focus on specific aspects of plant nitrogen nutrition seeking to identify molecular and physiological targets to improve nitrogen use efficiency through breeding and biotechnological approaches. There are then a series of excellent individual chapters on phosphorus, the cationic macronutrients potassium, calcium and magnesium, sulphur, iron, zinc and the micronutrients boron, chlorine, copper, manganese, molybdenum and nickel. These chapters describe the physiological roles of each element, the molecular biology of their acquisition, biochemistry and redistribution within the plant, and the molecular or genetic targets for improving nutrient use efficiency. The book concludes with case studies describing (a) the interactions between drought and plant mineral nutrition, (b) the development of salt-resistant crops and (c) strategies to utilise nitrogen fixation by legumes for sustainable agriculture.