This book is mainly intended for students in mechanical engineering, but it may also serve well for practising engineers as a practical technical introduction to materials science. Contents are based on lectures of the author held for undergraduate students in mechanical engineering. The book also contains numerous graphs, tables, and explanations that can prove useful even for experienced matrial scientists and researchers. Contents cover both the fundamental and applied aspects of materials science. The first half of the book covers the basic principles of materials science, the behavior of crystalline materials, and the underlying materials concepts related to the mechanical properties of materials. The second half focuses on applied materials science. This includes coverage of the common alloys systems such as carbon steels, alloyed steels, cast iron, and nonferrous alloys.