  I discuss our ongoing Owens Valley Millimeter Array observations and Keck
near-infrared wavelength observations of the high-redshift sub-mm population of
galaxies. These observations are important for our understanding of the distant
universe since the sub-mm population accounts for a large fraction of the
extragalactic background at mm/sub-mm wavelengths and contributes significantly
to the total amount of star-formation and AGN activity at high redshift. The CO
data suggest that the sub-mm galaxies are analogous to the gas-rich
ultraluminous systems found in the local universe. Initial near-infrared data
show that many of the sub-mm galaxies are faint-red sources which are
undetected at ultraviolet/optical wavelengths. These results highlight the
importance that future sensitive mm-wavelength instruments, such as the LMT and
ALMA, will have on our understanding of the early evolution and formation of
galaxies.
