Quark-gluon plasma

An elementary introduction to the physics of quark-gluon plasma is given. W e start with a sketchy presentation of the Quantum Chromodynamics which is the fundamental theory of strong interactions. The structure of hadrons bui lt up of quarks and gluons is briefly discussed with a special emphasis on the confinement hypothesis. Then, we explain what is the quark-gluon plasma and consider why and when the hadrons can dissolve liberating the quarks a nd gluons. The heavy-ion collisions at high-energies, which provide a uniqu e opportunity to get a droplet of the quark-gluon plasma in the terrestrial conditions, are described. We also consider the most promising experimenta l signatures of the quark-gluon plasma produced in nucleus-nucleus collisio ns. At the end, the perspectives of the quark-gluon plasma studies at the f uture accelerators are mentioned.