"Compound Semiconductors 2004" was the 31st Symposium in this distinguished international series, held at Hoam Convention Center of Seoul National University, Seoul, Korea from September 12 to September 16, 2004. It attracted over 180 submissions from leading scientists in academic and industrial research institutions, and remains a major forum for the compound semiconductor research community since the first one held in 1966 at Edinburgh, UK under the name of 'International Symposium on Gallium Arsenide and related Compounds'. These proceedings provide an international perspective on the latest research and an overview of recent, important developments in III-V compounds, II-VI compounds and IV-IV compounds. In the total of 106 papers, notable progress was reported in the development of zinc oxide and spintronics. Steady advances were seen in traditional topics such as III-V based electronic and optoelectronic devices, growth and processing, and characterization. Novel research trends were observed in quantum structures, such as quantum wires and dots, which are promising for future developments in nanotechnology. As the primary forum for research into these materials and their device applications the book is an essential reference for researchers working on compound semiconductors in semiconductor physics, device physics, materials science, chemistry and electronic and electrical engineering.