Metallic alloys serve important roles for many types of technology, as they have a broader range of properties than almost all other materials. In fact, there are several thousand standard alloys already in existence and new ones are continuously developed for better performance or to meet new demands. Metallography is the study of the composition and microstructure of all types of metallic alloys. The microstructure - inclusions, grains, or matrix - has a significant effect on the macroscopic properties of alloys, e.g., tensile strength, elongation, and both thermal and electrical conductivity. The understanding of the relationship between composition, microstructure, and macroscopic properties plays a key role in the development and manufacture of alloys, where metallography is often exploited. These same investigative principles can be applied to the characterization of any type of solid material. Different types of experimental techniques are used to reveal the microstructure of metallic alloys. Since the last century, most investigations are carried out with incident light microscopy using bright field, dark field, differential interference contrast (DIC), and color (tint) etching. Presently, computer automated microscopes and image analysis systems provide a rapid and accurate method for the metallographic assessment of alloys, as well as, other materials.