  Observations at far-infrared and submillimeter wavelengths promise to
revolutionize the study of high redshift galaxies and AGN by providing a unique
probe of the conditions within heavily extinguished regions of star formation
and nuclear activity. Observational capabilities in this spectral region will
expand greatly in the next decade as new observatories are developed both in
space and on the ground. These facilities include the Space Infrared Telescope
Facility (SIRTF), the far-infrared and submillimeter telescope (FIRST), and the
millimeter array (MMA). In the longer term, the requirements of high angular
resolution (comparable to that of HST), full wavelength coverage, and high
sensitivity (approaching the fundamental limit imposed by photon counting
statistics) will motivate the development of far-IR and submillimeter space
interferometry using cold telescopes and incoherent detector arrays.
