Organized by Professor Tsunemasa Taguchi of Yamaguchi University, Japan, the first International Conference on White LEDs and Solid State Lighting (White LEDs 2007) was held in Tokyo, Japan during November 26-30, 2007 with great success, drawing approximately 600 attendees. Different from other nitride meetings, this conference was designed to promote the development of light-emitting device technology (UV, color, and white) aimed at solid state lighting (SSL) and other related applications. It covered a broad scope of topics from related material preparation, device design and process, to SSL science and technology and its various applications. In particular, novel structure and application of light-emitting devicewerean important issue at the conference. The materials, based on which the light-emitting device was fabricated, were not limited to nitride semiconductors. All other semiconductors, including ZnO, inorganic phosphors, and organic/polymer materials, were included. This conference provided a platform for the material scientists/engineers to communicate with the device and application communities. The dialogue between the device design and system application specialists also bridged the gap between the demand and supply parties. Furthermore, this conference increased mutual understanding by creating an opportunity for the academia to meet the industrial and governmental decision makers.