The Terahertz (THz) portion of the electromagnetic spectrum (freq. ~ 1–10 THz; λ ~ 300–30 μm) provides us with a powerful window into cosmic evolution. THz photons arriving at Earth can yield valuable insights into everything from the birth and death of stars to the cataclysmic events associated with the origin of galaxies and the Universe itself. Most of the THz photons we observe are emitted by the gas and dust between the stars, that is, the interstellar medium (ISM). At THz frequencies we can observe photons associated with the ISM of our own galaxy, the Milky Way, as well as from the ISM's of distant galaxies. The evolution of THz astronomy has been driven largely by two factors: (1) atmospheric absorption of THz light; and (2) the availability of detector technology. Water vapor in the Earth’s atmosphere is a very efficient absorber of THz photons. Therefore, THz observations are best conducted from space-based telescopes, balloon-borne telescopes, airborne observatories, or telescopes at high, dry, cold sites on Earth. Our team is involved in all aspects of THz astronomy; from developing detection systems and telescopes for ground, air, and space to utilizing THz observations to better understand our cosmic origins.