A review of the recent results obtained in the Nambu–Jona–Lasinio model is given. In particular, the following topics are discussed in detail: the effects of screening of the meson fields at finite temperature and density, the temperature dependence of the quark condensate in the approach including meson loops, the formulation of a chirally invariant transport theory for quark matter and, finally, the critical scattering at the chiral phase transition. Our presentation of the new results follows the general introductions to the ultra-relativistic heavy-ion collisions and to the imaginary/real time formalism.
