  After introducing essential, qualitative concepts and results, we discuss the
application of Dyson-Schwinger equations to QCD at finite T and mu. We
summarise the calculation of the critical exponents of two-light-flavour QCD
using the chiral and thermal susceptibilities; and an algebraic model that
elucidates the origin of an anticorrelation between the mu- and T-dependence of
a range of meson properties. That model also provides an algebraic
understanding of why the finite-T behaviour of bulk thermodynamic properties is
mirrored in their mu-dependence, and why meson masses decrease with mu even
though f_pi and -<q-bar q> increase. The possibility of diquark condensation is
canvassed. Its realisation is uncertain because it is contingent upon an
assumption about the quark-quark scattering kernel that is demonstrably false
in some applications; e.g., it predicts the existence of coloured diquarks in
the strong interaction spectrum, which are not observed.
