Book excerpt: A description of the design principles, seen mainly from the fabrication point of view. Following a review of the historical development and of the materials used in lasing at short to long wavelengths, the book goes on to discuss the basic design principles for semiconductor-laser devices and the epitaxy for laser production. One entire chapter is devoted to the technology of liquid-phase epitaxy, while another treats vapor-phase and beam epitaxies. The whole is rounded off with mode-control techniques and an introduction to surface-emitting lasers.