  I present recent results on the theory of QCD matter production in high
energy heavy ion collisions and on the interactions of heavy quarks in such
environment. The centrality and rapidity dependence of hadron production is
evaluated in semi--classical approach. The energy loss of heavy quarks in
matter is computed. The heavy--to--light meson ratio (e.g., D/pion) at moderate
transverse momenta is demonstrated to be both sensitive to the density of color
charges in the medium and infrared stable.
