Significant scientific and technical challenges remain within the terahertz (THz) frequency regime and they have motivated an array of research activities. Indeed, one research frontier in high frequency electronics now lies in the so-called THz (or submillimeter-wave) regime between the traditional microwave and the infrared domains. Major research programmes have emerged that focus on advancing the state of the art in THz frequency electronic technology and on investigating novel applications of THz frequency sensing. This manual seeks to serve as a detailed reference for the THz frequency technological advances that are emerging across a wide spectrum of sensing and technology areas.