In the last two decades, space and ground-based observations have revolutionized our understanding of the remnants of stellar evolution, the white dwarf stars. We now have a detailed picture of the evolution of the surface composition of hot white dwarfs, those objects with temperatures above about 20 000 K, as they cool. Significant quantities of heavy elements are supported by radiation pressure against the downward pull of gravity in the very hottest examples (above 40 000 K) but, once the efficiency of the mechanism diminishes below 40 000 K, they fall rapidly out of the atmosphere. However, while the observational results are qualitatively consistent with the predictions of theoretical calculations, the measured element abundances differ substantially from those expected. A viable explanation, supported by good observational evidence, is that the surface composition is further modified through the loss of material in a weak wind. This paper reviews recent developments, made in particular with the International Ultraviolet Explorer, Roentgen Satellit and Extreme Ultraviolet Explorer, setting them in the context of our earlier picture of white dwarf evolution to show the important advances made.