Nitrogen fertilizers are essential for increasing agricultural production and ensuring food security. However, their inefficient use is due to inherent limitations of crop plants and the way nitrogen fertilizers are formulated, applied, and managed. The main objective of this book is to evaluate various aspects of nitrogen fertilizers fate in the context of overall nitrogen inputs to agricultural systems. The goal is to enhance nitrogen use efficiency and reduce negative environmental impacts. The cross-cutting issues addressed in the book include improving nitrogen use through emerging technologies (genetic enhancement, QTL mapping), understanding nitrogens interactions with other nutrients to meet nitrogen needs, and mitigating nitrogen losses caused by environmental factors and management practices. Nitrogen Use Efficiency in Plants bridges the gap between basic and applied research and practical crop production. The book covers a wide range of topics related to nitrogen use efficiency, plant and crop responses to nitrogen fertilizers, nitrogen acquisition and reduction, molecular approaches, nitrate induction and signaling, and nitrogen use under abiotic stresses. This book is an invaluable resource for academics and researchers working in plant physiology, biochemistry, biotechnology, molecular breeding, and agronomy. It provides a comprehensive, interdisciplinary description of the problems related to the efficient use of nitrogen in agriculture, making it an essential professional resource for those working in plant and crop systems.