The evolution of Si-based optoelectronics has been extremely fast in the last few years and it is predicted that this growth will still continue in the near future. The aim of the volume is to present different Si-based luminescing materials as porous silicon, rare-earth doped silicon, Si nanocrystals, silicides, Si-based multilayers and silicon-germanium alloy or superlattice structures. The different devices needed for an all-Si-based optoelectronics are treated, ranging from light sources to waveguides, from amplifiers and modulators to detectors. Both the very basic treatments as well as a.