Soybeans are legumes, native to East Asia, that are grown for oil and protein around the world. Cultivated primarily in warm and hot climates, soybeans were originally used as nitrogen fixers in early systems of crop rotation – ancient farmers would plant a field of soybeans on an exhausted or depleted field and then plow the crop under to replenish the soil. Development of use technologies such as fermentation and processing for oil has led to many new applications of this useful plant. This article will discuss the origin and development of the soybean, its cultivation and usage, and the crop’s important role in the world economy.