It is said that one should not judge a book by its cover, but maybe one can assess a book on the basis of the promise of its preface? Here the authors carefully explain their motivation and methodology for preparing this magisterial treatment of band structure in the technologically important III–V semiconductor material system. Their motivation to clearly explain the underlying principles shines through the well-written and well-illustrated text. A key element of the methodology is to offer a volume that is as self-contained as possible; this is achieved admirably. Having firmly embedded the underlying principles, the authors focus attention on device applications—in most cases topics where the authors have undertaken seminal research. Here inter-band semiconductor lasers and LEDs, quantum cascade lasers and solar cells provide particularly cogent exemplars of using the fundamental principles. However, the authors are also alert to the fact that new horizons open as application areas mature. In this respect, they provide the attentive reader with an entry into burgeoning new areas such as graphene. This way, they ensure that this volume will be a crucial reference point for present and future generations of researchers and technologists.