This book reviews the four classes of materials science, the study of each of which are also considered separate fields: metals, ceramics, polymers and composites. The application of materials science in energetic materials, like explosives and oxidizers, is also an important topic, and thus is extensively reviewed in this book. Furthermore, the microhardness of steel and the various testing methods in polymers is analyzed. Specifically, the Vickers microhardness of iron, carbon steels and high-alloyed steels are reviewed. Other chapters in this book explore the process of percolation in cuprate composites. Recently, extensive interest has been focused on the percolation processes in superconducting cuprates, of which physical properties are strongly characterized by the low-dimensional aspects of the crystal structures. Bulk metal glasses (BMGs) are also examined, which are currently the focus of intense research in the world because of their excellent properties and potential applications as engineering materials and functional devises. Other chapters in this book focus on electrodeposition and corrosion properties of zinc-cobalt and zinc-cobalt-iron, the structure and morphology of electrodeposited nickel-cobalt alloy powders, the control of microstructures by heat treatments and high-temperature properties, and the evaluation of fatigue strength methods for machine designs.