Semiconductor nanowires exhibit novel electronic and optical properties due to their unique one-dimensional structure and quantum confinement effects. In particular, III-V semiconductor nanowires have been of great scientific and technological interest for next generation optoelectronic devices including transistors, light emitting diodes, lasers, photodetectors, and solar cells. is an account of recent progress in the synthesis, characterization, physical properties, device fabrication, and applications of binary compound and ternary alloy III-V semiconductor nanowires. Each chapter is prepared by renowned experts in the field, describing the current state of knowledge and key areas of research. The book is written at the expert level, but also serves as a guide for researchers or graduate students aiming to enter semiconductor research.