Dust is but a small fraction of the mass of a galaxy
 yet it plays a crucial role in  galactic evolution.  We are well
 aware of how dust influences our observations of distant stars and
 how easily dust may mislead us with regard to the way in which
 stars are distributed within the Galaxy, but how does it affect
 our view of other galaxies ? Until recently most astromomers
 would have said that dust has very little effect on our
 understanding of the global properties of galaxies, but this
 view has changed dramatically now that better radiative
 transfer models and observational data are available. The
 major problem we intend to solve with the proposed observations
 is "what is the fraction of stellar flux in galaxies which is
 reprocessed through dust ?". This is the dust opacity problem
 and at the moment opinions vary enormously as to the typical
 value of the optical depth, and how influential this issue is with
 regard to our understanding of galaxies. We feel that the
 decisive observation is to measure the contribution cold
 (<20K) dust makes to the FIR output of galaxies and how this dust
 is distributed within galaxies. We plan to map at 200u a sample
 of 24 (22) nearby galaxies (about 20 hrs of observation)
 which are large enough to give some
 information on the spatial distribution of cold dust. Our chosen
 sample have resolved IRAS 60 and 100u data. If galaxies
 have high opacities they must emit a large fraction of their
 bolometric luminosity in the FIR part of the spectrum. These
 observations specificaly address issues such as the correlations
 among galaxy global properties, hidden mass, absorption of high z
 QSO's and primeval galaxies, Tully-Fisher correlations, gas-to-dust
 gas-to-stars ratios and the 'starburst' and hidden AGN phenomona.