This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book represents the entire field of Agricultural Economics at an advanced level. It integrates microeconomics, macroeconomics, production and consumption, finance, international trade, natural resources and the environment, marketing, management, business, econometrics, and other sub-disciplines. Agricultural Economics started as a profession by applying farm management and economic and business principles to farms. The current subject covers food from farm to fork and all the important resources influenced by agriculture such as land, water, clean air, environment, animals, rural development, education, forestry, trade, restaurants, oil, gas, agribusinesses, and farms. The agricultural economist's position is to build "economic models" to explain and predict the new production and consumption patterns. Hypoxia and other factors affecting the planet can be studied and research may find alternative ways to adjust to these influences or reduce their impact on human utility and comfort.