Physics and applications of terahertz radiation This book covers the latest advances in the techniques employed to manage the THz radiation and its potential uses. It has been subdivided in three sections: THz Detectors THz Sources Systems and Applications. These three sections will allow the reader to be introduced in a logical way to the physics problems of sensing and generation of the terahertz radiation the implementation of these devices into systems including other components and finally the exploitation of the equipment for real applications in some different field. All of the sections and chapters can be individually addressed in order to deepen the understanding of a single topic without the need to read the whole book. The THz Detectors section will address the latest developments in detection devices based on three different physical principles: photodetection thermal power detection rectification. The THz Sources section will describe three completely different generation methods operating in three separate scales: quantum cascade lasers free electron lasers and non linear optical generation. The Systems and Applications section will take care of introducing many of the aspects needed to move from a device to an equipment perspective: control of terahertz radiation its use in imaging or in spectroscopy potential uses in security and will address also safety issues. The text book is at a level appropriate to graduate level courses up to researchers in the field who require a reference book covering all aspects of terahertz technology