Since this book is intended to be self-contained, several chapters introduce fundamental principles that are essential to a formulation of linear piezoelectricity. Chapters 2, 3, and 4 review the requisite background and supporting principles from mathematics, continuum mechanics, and continuum electrodynamics, respectively. In this section we review topics from the study of vibrations of linear structures that are used throughout Chapters 5, 6, 7, and 8. This review is necessarily brief, and a full account can be found in any of the excellent texts on this classical topic in mechanics. See for example [21, 29, 30], or [11].