Interest in Terahertz science has expanded rapidly in recent years due largely to the advent of fast-pulse laser time domain spectrometers (TDS), which have allowed researchers in a wide variety of fields to explore imaging and spectroscopy applications in this rather unique wavelength regime. However Terahertz spectroscopy dates back to at least the mid 1970's, and for many years was the purview only of radio astronomers, quantum chemists, and a few plasma physicists, who used traditional RF and spatial Fourier Transform techniques to explore this frequency range. This short conference talk will review both the traditional applications for Terahertz instruments in astronomy and space science as well as a variety of new applications from biology and medicine to ultrafast physics and chemistry. Emphasis is placed on imaging, since this forms the core of many of the activities that are drawing attention to this evolving field