We propose to make fully-sampled maps of the Serpens Cloud
 Core at three different wavelengths using the PHT-C arrays.
 Our goal is to obtain high-resolution images of the
 protostellar sources in this cluster, including the Class 0
 sources which represent the earliest observable stage of
 star formation. By resolving the individual sources we can
 obtain flux densities at 60, 100, and 160 um. Combined with
 existing mm & submm photometry, the ISO results will allow
 us to accurately determine the spectral energy distribution
 of these protostars and determine their temperatures,
 luminosities, and dust masses. ISO imaging is necessary to
 properly identify and separate the closely spaced ( ~ 1')
 Class I and candidate Class 0  sources in this actively star-
 forming cloud core.