This handbook provides comprehensive knowledge on device and system technologies for seamlessly integrated networks of various types of transmission media such as optical fibers and millimeter and THz waves to offer super high-speed data link service everywhere. The seamless integration of the knowledge of radio and optical technologies is needed to construct wired and wireless seamless networks. High-frequency bands such as millimeter-wave and THz-wave bands where super wideband spectra are available can offer high-speed data transmission and high-resolution sensing. However, the expected coverage is limited due to large wave propagation loss. Thus, convergence of radio and optical links is indispensable to construct worldwide networks. The radio and optical technologies share the same physics and are closely related to each other but have been developed independently. Therefore, there is a big gap between these two fields. Bridging the two fields, this handbook is also intended asa common platform to design integrated networks consisting of wireless and wired links. Full coverage of wireless and wired convergence fields ranging from basics of device and transmission media to applications allows the reader to efficiently access all the important references in this single handbook. Further, it also showcases state-of-the-art technology and cases of its use.