  The extragalactic background light (EBL), exclusive of the cosmic microwave
background, consists of the cumulative radiative output from all energy sources
in the universe since the epoch of recombination. Most of this energy is
released at ultraviolet and optical wavelengths. However, observations show
that a significant fraction of the EBL falls in the 10 to 1000 micron
wavelength regime. This provides conclusive evidence that we live in a dusty
universe, since only dust can efficiently absorbs a significant fraction of the
background energy and reemit it at infrared wavelengths. The general role of
dust in forming the cosmic infrared background (CIB) is therefore obvious.
However, its role in determining the exact spectral shape of the CIB is quite
complex. The CIB spectrum depends on the microscopic physical properties of the
dust, its composition, abundance, and spatial distribution relative to the
emitting sources, and its response to evolutionary processes that can modify
all the factors listed above. This paper will present a brief summary of the
many ways dust affects the intensity and spectral shape of the cosmic infrared
background. In an Appendix we present new limits on the mid-infrared intensity
of the CIB using TeV gamma-ray observations of Mrk 501.
