  This paper attempts to give an overview about sufficiency in the setting of
quantum statistics. The basic concepts are treated paralelly to the the measure
theoretic case. It turns out that several classical examples and results have a
non-commutative analogue. Some of the results are presented without proof (but
with exact references) and the presentation is intended to be self-contained.
The main examples discussed in the paper are related the Weyl algebra and to
the exponential family of states. The characterization of sufficiency in terms
of quantum Fisher information is a new result.
