Work performed on vanadia/titania catalysts at Brunel University over the past 20 years is summarised, and the thinking that led to the concept of reactive oxide monolayers is described. Both impregnation and grafting techniques lead to monolayers, and their structure, and that of the supramonolayer region is revealed through characterisation by a number of physical techniques. Factors responsible for the stability of monolayer systems are considered, and the basis of their activity in selective oxidations is discussed.