Understanding Modern Transistors and Diodes is a textbook on semiconductor devices with three objectives: (i) to provide a rigorous, yet readable, account of the theoretical basis of the subject of semiconductor devices; (ii) to apply this theory to contemporary transistors and diodes so that their design and operation can be thoroughly understood; (iii) to leave readers with a sense of confidence that they are well equipped to appreciate the workings of tomorrow's devices, and to participate in their development.

There are many books on semiconductor devices, often with similar objectives, and it is reasonable to ask: why write another one? The answer is two-fold: firstly, after teaching and researching in the area for 40 years, I have a strong personal viewpoint on how the subject can best be presented to students; secondly, we are at a particularly interesting point in the development of the subject – we are at the micro/nano boundary for high-performance transistors, and we are on the threshold of seeing optoelectronic diodes make a contribution to our planet's sustainability.

These circumstances are new, and are quite different from those of 20 years ago when I was last moved to write a book on semiconductor devices. At that time the major development was the incorporation of thousands of transistors into monolithic integrated circuits.