  A general overview on the role of heavy quarks as probes of the medium formed
in high energy nuclear collisions is presented. Experimental data compared to
model calculations at low and moderate pT are exploited to extract information
on the transport coefficients of the medium, on possible modifications of heavy
flavor hadronization in a hot environment and to provide quantitative answers
to the issue of kinetic (and chemical, at conceivable future experimental
facilities) thermalization of charm. Finally, the role of heavy flavor at high
pT as a tool to study the mass and color-charge dependence the jet quenching is
also analyzed.
