This book sets out to explain the development of modern electronic systems and devices from the viewpoint of the semiconductor materials (germanium, silicon, gallium arsenide and many others) which made them possible. It covers the scientific understanding of these materials and its intimate relationship with their technology and many applications. It began with Michael Faraday, took off in a big way with the invention of the transistor at Bell Labs in 1947 and is still burgeoning today. It is a story to match any artistic or engineering achievement of man and this is the first time it has been presented in a style suited to the non-specialist. It is written in a lively, non-mathematical style which brings out the excitement of discovery and the fascinating interplay between the demands of system pull and technological push. It also looks at the nature of some of the personal interactions which helped to shape the modern technological world.