In many ways interfaces and surfaces dominate the behaviour of not only bulk polymers but also thin film behaviour. The critical nature that the interface plays on numerous physical properties has stimulated significant effort to understand such behaviour. A number of theoretical models, particularly using mean-field approximations, have been developed to predict critical parameters associated with these interfaces and surfaces. Only with the advance of a number of powerful techniques have the finer details of such theories been able to be critically tested. This paper reviews both the relevant theories and experimental work associated with predominantly polymer-polymer interfaces, with particular emphasis on capillary waves, dewetting, patterning, diffusion and adhesion. (C) 2003 Elsevier Ltd. All rights reserved.