Fertilizers are indispensable for agricultural production. Chemical fertilizers have significantly improved agricultural productivity. However, the excessive use of fertilizers has caused serious nitrogen pollution. What is the reason of a lack of progress in addressing nitrogen pollution? What is necessary to achieve sustainable nitrogen use in agriculture? This book provides a new perspective from an economic standpoint on these questions. Firstly, we propose the non-market valuation methods to evaluate the social costs of nitrogen. Because nitrogen control requires considerable effort and cost, evaluating the costs and benefits of nitrogen measures in monetary terms allows for a comparison of the expenses and benefits of nitrogen control, despite the delays in implementing such measures in the agricultural sector. Secondly, we analyze the behavioral changes of producers and consumers regarding nitrogen to indicate the direction of agricultural environmental policies for sustainable nitrogen use in the future. To achieve sustainable nitrogen use, farmers and consumers need to adopt production and consumption behaviors that consider nitrogen. By analyzing the effects of "visualizing" the nitrogen footprint on the behavioral changes of farmers and consumers, this book not only highlights the limitations of conventional agricultural policies but also provides recommendations for future agricultural environmental policies.