Detection of primeval galaxies is a direct approach to understand the
 formation of galaxies, galaxy clusters,  and large-scale structure of
 the universe. It was suggested that a galaxy in its first star-forming
 phase would be a strong Ly-alpha emitter; a SFR would be 1000
 M(solar)/yr with L = 3 x 10 ^ 11 M(solar)/yr, if a typical elliptical
 galaxy with a mass of 3 x 10 ^ 11 M(solar) was formed in 0.3 Gyr.
 However, no such population has been unambiguously identified despite
 of intensive Ly-alpha search campaigns. If primeval galaxies are
 luminous as suggested, but obscured by dust, ISO can provide the
 unique opportunity to investigate this hypothesis.
 Hence, we propose to search for primeval galaxies in 11 fields
 centered on known high-redshift objects by conducting ISOCAM LW2
 (6.7 um) imaging and ISOPHOT-C C_90 (90 um) and C_160 (160 um)
 mapping.  We choose to use known high-redshift objects as markers of
 possible clusters or protoclusters rather than attempt a completely
 unbiased search, since the purpose is to detect any kind of primeval
 galaxies.  For this, a QSO with damped Ly-alpha systems is an ideal
 object, since multiple markers are available in that direction.