Mechanisms of Confinement

We discuss current proposals for the mechanism of color confinement in QCD. The role of topological excitations like vortices and monopoles is analyzed, starting from the numerical evidence produced by Monte Carlo simulations. Trying to characterize the deconfinement phase transition in terms of symmetry, we argue that the confined phase can be characterized as a dual superconducting phase, i.e. a phase where a dual magnetic symmetry is spontaneously broken à la Higgs. We discuss the definition of a disorder parameter that is capable of monitoring dua superconductivity and present numerical data in favour of a deconfining phase transition in pure gluodynamics driven by monopole condensation. This picture can be naturally extended to the case of QCD with dynamical fermions: in this case, the disorder parameter becomes a unique tool to identify the phase transition.