Book review: Piezoelectricity in Classical and Modern Systems Morten Willatzen | Review by Christian Brosseau Piezoelectricity is a phenomenon in which materials respond to a mechanical strain by generating electrical polarization or, conversely, respond to an applied external electric field by generating a mechanical strain. While this effect was discovered in the 1880s, this subject remains very active, since it allows for a variety of applications in sensing, actuating, transducing, energy harvest and conversion. Willatzen’s book is an introduction to the basic concepts of piezoelectricity. It is a pleasure to read and contains careful discussions of symmetry operations, since the lack of centrosymmetry is essential for piezoelectric materials. Optics and photonics students will find a complete chapter dedicated to the optical properties of piezoelectric materials. I highly recommend this book as primary source for graduates and scientists involved in this area of research and en...