The confinement

Various aspects and mechanisms of QCD colour confinement are surveyed. Following the introduction of gauge-invariant order parameters, a field-correlator definition of the phenomenon is given, and a class of correlators responsible for confinement is explicitly separated. It is shown that, in terms of effective Lagrangians, confinement is a dual Meissner effect, and for its quantitative description the popular Abelian projection method is used, which is explained in detail. To determine the field configurations responsible for confinement, classical solutions are analysed using a newly-developed criterion. Finally, all aspects of confinement are illustrated by a simple example of string formation for a quark moving in a field of heavy antiquark.