Terahertz (THz) radiation offers innovative sensing and imaging technologies that can provide information unavailable through conventional methods such as microwave and X-ray techniques. With the advancement of THz technologies, THz sensing and imaging will impact a broad range of interdisciplinary fields. THz radiation in the range of 0.1-10 THz induces low-frequency crystalline lattice vibrations, hydrogen-bond stretching, and other normal vibrational modes of molecules in many chemical and biological materials including ERCs, drugs and other biomolecules. The transmitted or reflected THz spectra of these materials contain THz fingerprints which provide rich information unavailable in other electromagnetic spectra. THz waves with low photon energies (4 meV for 1 THz, one million times weaker than X-ray photons) will not cause harmful photo ionization in biological tissues. As a potential sensing and imaging modality, THz radiation is considered a safe method for the operators and targets. THz radiation can penetrate through many non-polar dielectric materials including paper, cardboard, textiles, plastics, wood, leather and ceramics, with little attenuation. Therefore, THz technologies can be used for nondestructive/noninvasive sensing and imaging of targets under covers or in containers. I will report recent development of THz wave generation, detection, and applications. @FootnoteText@ * For AVS meeting, San Francisco, November, 2006.