In this ninth edition we have retained the objectives and approaches for teaching materials science and engineering that were presented in previous editions. The first, and primary, objective is to present the basic fundamentals on a level appropriate for university/college students who have completed their freshmen calculus, chemistry, and physics courses. The second objective is to present the subject matter in a logical order, from the simple to the more complex. Each chapter builds on the content of previous ones. The third objective, or philosophy, that we strive to maintain throughout the text is that if a topic or concept is worth treating, then it is worth treating in sufficient detail and to the extent that students have the opportunity to fully understand it without having to consult other sources; in addition, in most cases, some practical relevance is provided. The fourth objective is to include features in the book that will expedite the learning process. These learning aids include the following: