This book highlights the growing applications of THz technology and various modules used for their successful realization. The enormous advantages of THz devices like higher resolution, spatial directivity, high-speed communication, greater bandwidth, non-ionizing signal nature and compactness make them useful in various applications like communication, sensing, security, safety, spectroscopy, manufacturing, bio-medical, agriculture, imaging, etc. Since the THz radiation covers frequencies from 0.1THz to around 10THz and highly attenuated by atmospheric gases, they are used in short-distance applications only. The book focuses on recent advances and different research issues in terahertz technology and presents theoretical, methodological, well-established and validated empirical works dealing with the different topics.