Functionally graded material (FGM) belongs to a class of advanced composite materials that is characterized by variation in composition, microstructure, as well as properties across the dimension of the material. The properties of FGM are different from any of the individual materials that make up the composite. In this chapter, an introduction to the functionally graded material is presented. A brief background to the functionally graded material and the presence of FGM in nature are also discussed. The chapter ends with a summary.