Phase transitions in two dimensions

Recent developments - both theoretical and experimental - in the understanding of phase transitions in two-dimensional systems are reviewed. Topics discussed include the classification and characterization of order/disorder transitions in adsorbed monolayers, the breakdown of universality, superfluidity in helium films and the critical behaviour of the two-dimensional XY model, Abelian and non-Abelian symmetry and the analogies between the theory of phase transitions in two dimensions and quantum field theory, especially quark confinement, in four-dimensional space time.