[en] Reconnection is a universal plasma-physics process which has as one of its main characteristics the energization of plasma through the conversion of magnetic field energy. Interest in reconnection is multidisciplinary, and reconnection-associated phenomena are observed in astrophysical, solar system and laboratory plasmas. To highlight the potential of reconnection for practical applications, this process is described from a general point of view and a theoretical model is presented which is applicable to both non-relativistic and relativistic plasmas. Relativistic plasmas can be created under laboratory conditions, and the model predicts that such plasmas could be energized to very high energies. Experiments on reconnection may therefore lead to practical applications, such as hot plasma injectors in fusion reactors. It is suggested that fusion reactors such as the tokamak can be modified so that plasma heating through reconnection is intrinsic to the device. (author)