The objective of this chapter is to address the three basic questions of composite materials and structures in Figure 1-1: (1) What is a composite material? (2) Why are composite materials used instead of metals? and (3) How are composite materials used in structures? As part of The What, the general set of composite materials will be defined, classified, and characterized. Then, our attention will be focused on laminated fiber-reinforced composite materials for this book. Finally, to help us understand the nature of the material we are trying to model with mechanics equations, we will briefly describe manufacturing of composite materials and structures. In The Why, we will investigate the advantages of composite materials over metals from the standpoints of strength, stiffness, weight, and cost among others. Finally, in The How, we will look into examples and short case histories of important structural applications of composite materials to see even more reasons why composite materials play an ever-expanding role in today’s and tomorrow’s structures. Basic Questions of Composite Materials and Structures https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781315272986/78b03905-908e-46c6-8445-b0abaf620955/content/fig1_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>