The book presents the structural or constitutional details of different materials which lead to differences in their behavior and their properties such as physical, Mechanical, chemical, electrical, thermal and magnetic. The text includes Atomic models and bondings, Crystallography and imperfections, Mechanical Properties and testing, Phase diagrams and Equilibrium diagrams, ferrous and non-ferrous materials, heat treatments, magnetic properties, electric properties, ceramics, plastics, optical and thermal materials including concrete and Composite materials, fracture and fatigue, corrosion and its control.