The story of semiconductors, laced with the discovery of the laws of the microworld so different from ordinary human experience, has resulted in a fundamental transformation of our understanding of the world and in an equally fundamental transformation of the world itself. Artificial structures based on semiconductors now make it possible to store and process previously unimaginable amounts of information, but also to retrieve and remotely transmit previously unimaginable amounts of information in the form of various sensors and detectors. It is only thanks to semiconductors that artificial light has ceased to be an energetically expensive rarity.