We propose to use ISO to study the FIR energy distribution and
to determine the FIR luminosity function for high redshift(z$>$4)
radio quiet QSOs as part of a systematic investigation into the
molecular content, dust mass, dust emissivity and dynamics of high
redshift objects.  The targets will be selected from a sample of the
known ~60 radio quiet QSOs with z$>$4. Observing priorities will
be based on their ISO visibility, optical luminosities, and previous
submm/mm observations at the IRAM 30m and JCMT to maximise the
scientific impact.
NOTE: THIS PROPOSAL IS NOT ASKING FOR TIME TO OBSERVE ALL 48 TARGETS
THAT ARE LISTED IN THE OBSERVATION_SUMMARY_FORM. TIME IS
REQUESTED FOR 10 TARGETS.