This book highlights emerging trends in terahertz engineering and system technologies, mainly, devices, advanced materials, and various applications in THz technology. It includes advanced topics such as terahertz biomedical imaging, pattern recognition and tomographic reconstruction for THz biomedical imaging by use of machine learning and artificial intelligence, THz imaging radars for autonomous vehicle applications, THZ imaging system for security and surveillance. It also discusses theoretical, experimental, established and validated empirical work on these topics and the intended audience is both academic and professional.