This book is dedicated to the basic training of students of engineering in the field of physical metallurgy. One of the most serious problems confronting the engineer is the selection, treatment, and use of metals and alloys. These problems cannot be left entirely left entirely to the specialist known as the metallurgist, but must be dealt with to an appreciable extent by the engineer. No engineering project is without its problem of a material to do the job. To cope with this situation the engineer must have a basic understanding of the science and art of metallurgy as it is related to his interest. The authors have intended that this book should meet this need. While the purpose of this book in its second edition remains the same as in the first edition, there is a tendency to shift the emphasis to even more fundamental view. An even greater emphasis has been given to the fundamentals by adding three new chapters, namely, The Structure of Matter, Physical Properties, and Mechanical Properties.