This album contains macro- and microstructures of metals and alloys, flaws of steel and defects of its structures examined with optical microscopes. The main instruments are metallographic microscopes MIM-7 and MIM-8. The album is intended for students as a teaching aid for the courses "Material Science and Technology of Structural Materials", "Technology of Structural Materials", "Theory and Technology of Heat Treatment of Metals" and others. When studying alloy structures it is necessary to pay attention to the characteristic features of phase components: their color, shape and size of grains, their mutual arrangement, etc. It is best to first carefully examine the structure of the metal or alloy using a microscope. The magnification and degree of illumination should be chosen according to the teacher's recommendations.