Some of the earliest polarimetric measurements made in astronomy were
concerned with the polarization of the interstellar medium resulting
from dust grains aligned in the Galactic magnetic field. More than 50
years later, polarimetry continues to be an important diagnostic of
field structure on size scales ranging from planetary to galactic. The
use of both linear and circular polarimetry at optical and infrared
wavelengths can provide additional insights into the nature of dust
particles, their alignment in magnetic fields and the field
topology. Given the science benefits that polarimetry offers it is
perhaps surprising that the technique still seems to be a niche area
and that the continued existence of polarimetric facilities on current
and next generation large optical/IR telescopes needs to be ensured.
This presentation will review the technique of imaging polarimetry, the
science gains that have been achieved and the possibilities in the
near future.