This chapter defines food security as the condition reached when a nation’s population has access to sufficient, safe, and nutritious food to meet its dietary needs and food preferences. It stresses China’s importance to global food security because of its population size. The chapter introduces the contents of the volume and then treats briefly food security in ancient and dynastic (211 bc–1912) China. It examines environmental stressors, such as population growth, natural disasters, and insect pests as well as imperial responses (for example, irrigation, flood control, storage and transportation systems). The chapter also briefly introduces the Republican era (1912–1949) and compares environmental stressors and government responses then to those of the imperial period.