One of the areas in which small-angle neutron scattering (SANS) has had a profound impact over the last twenty years is the investigation of polymers and surfactants adsorbed at the solid/liquid and liquid/liquid interfaces. This is of course also an area of considerable commercial importance. Control of the structure of an adsorbed layer is thus a key priority of the colloid scientist. Equally important, however, is the ability to probe the arrangement of the adsorbed polymer molecules and to extract quantitative information from what might well be a complex, multicomponent system. SANS in combination with the principle of deuterium contrast variation is uniquely placed to provide this information.