This book highlights the comprehensive knowledge and latest progress in broadband terahertz (THz) technology. THz communication technology is believed to be one of the major choices that succeed the fifth-generation (5G) communication technology. With years of efforts, the author's team has created a number of world records in the generation, transmission, and reception of ultra wideband THz signal, realizing the MIMO transmission and reception of THz communication, the THz signal transmission with communication capacity of 1 Tbit / s, and the optical fiber and THz integrated transmission. A variety of linear and nonlinear algorithms for multi-carrier and single-carrier THz communication systems are developed, which greatly improves the transmission performance of broadband systems. The book covers in details the broadband THz signal generation, long-distance transmission, and high sensitivity detection. It is of great reference value for researchers, engineers, and graduate students in optical and wireless communications.