  The recent detection of the Cosmic Infrared Background in FIRAS and DIRBE
residuals, and the observations of IR/submm sources by the ISOPHOT and SCUBA
instruments have shed new light on the optically dark side of galaxy formation.
It turns out that our view on the deep universe has been so far biassed towards
optically bright galaxies. We now know that a significant fraction of
galaxy/star formation in the universe is hidden by dust shrouds. In this paper,
we introduce a new modelling of galaxy formation and evolution that provides us
with specific predictions in the IR/submm wavebands. These predictions are
compared with the current status of the observations. Finally, the future
all-sky and deep surveys with the PLANCK and FIRST missions are briefly
described.
