The changes which have taken place in electronics are truly astonishing. It is difficult to believe that within a single lifespan we have come from the cat's­ whisker diode, via the thermionic valve, to the 256K random access memory and beyond. These developments would not have come about without an increased understanding of the physics and technology of the solid state. Although the progression from Planck's quantum postulate to single chip electronic systems within eighty years has resulted in an increased level of specialisation of the fields of knowledge, solid state nevertheless continues to be a cross-disciplinary subject. The design and fabrication of solid state devices involve large elements of chemistry, physics and materials science. However, books on the subject tend to be written by specialists in one or other area. Thus a physics-based text is likely to have more details on quantum theory than is necessary for a technologist. Similarly, texts which concentrate on devices and their applications frequently ignore the fundamental background which is vital for a true understanding.