With significant progress made in recent years, vertical cavity surface emitting lasers (VCSELs) have emerged as potential lightwave sources with a variety of applications, including high speed optical interconnects, parallel data links, optical recording, 2-D scanning, and optical signal processing. This volume, which contains a collection of articles by outstanding experts on this topic, encompasses a broad discussion of the current trends in the development of VCSELs. Discussions include material growths, structure designs, processing methods, performance analysis, improvement strategies, and future prospects. The collection provides a comprehensive overview that may help newcomers to this field as well as engineers and researchers who are engaged in the research and development of this new exciting device family.