From IRAS data, we have identified a possible correlation between QSO
 FIR spectral energy distribution and host galaxy morphology, which, if
 confirmed, may be important in understanding the evolutionary history
 of the QSO phenomenon.  New ground-based observing techniques and the
 refurbished HST are producing detailed images of QSO host galaxies.
 Many of these images show features that broadly support interaction
 and merger scenarios for the origin and evolution of quasars, including
 double nuclei, bridges and tails, and previously unsuspected close
 companions.  We find that, of 34 QSOs detected by IRAS at 25, 60, and
 100 microns, the 3 that fall close to the region of the two-color
 diagram occupied by the ultra-luminous starburst galaxies are also the
 only 3 QSOs in this sample showing convincing tidal tails.  By using ISO
 to obtain photometry on a complete sample at higher redshift than was
 possible with IRAS we will be able to test this apparent correlation.
 Our sample comprises all quasars with 0.5 < z < 1.25 from the 3CR and
 Peacock-Wall surveys.  We currently have deep ground-based optical and
 near-IR imaging of a significant portion of the proposed sample, and we
 have scheduled HST Cycle 4 time for imaging several of these quasars.