This course offers a comprehensive overview of the properties and behaviour of light. It begins with the light transmission including ray optics and wave optics; followed by the generation of light by lasers and light-emitting diodes. Examples on various lasers will be given. Further topics include electro-optical devices for optical modulation, switching and scanning. The last chapter is the light detection, mainly by semiconductor photo-detectors. Numerous applications and engineering examples are presented throughout the course.