  Searches for low-metallicity galaxies are reviewed, focusing mainly on
efforts to discover systems that are relevant for use in measuring the
primordial helium abundance. Wide-field objective-prism surveys for blue or
emission-line galaxies have played a major role in this field. Previous surveys
and search techniques are highlighted. Preliminary results from our new survey
for emission-line galaxies, the KPNO International Spectroscopic Survey (KISS),
are presented. KISS is substantially deeper than previous photographic surveys,
and represents the next generation of wide-field slitless spectroscopic
surveys.
