Over the last two decades, the search for a compact, high-power semiconductor source has produced many designs and concepts for monolithic diode-laser arrays and optical amplifiers. However, only a few design approaches have emerged with the potential for producing high-power, high-brightness monolithic sources. Although semiconductor-diode lasers are the most compact, highest gain and most efficient laser sources, challenges remain in developing structures that will produce high-quality, diffraction-limited output beams. This book presents and analyzes the results of work performed over the last twenty years in the development of high-brightness diode-laser arrays.