Professor T. W. Healy is distinguished for his contribution in the fields of surface and colloid chemistry. He has published extensive definitive experimental information concerning the adsorption of metal ions at the oxide solution interface and for the charge, potential characteristics and ion distribution at surfaces in aqueous solutions for a variety of circumstances. This work in conjunction with his theoretical studies has considerably extended our knowledge of the electrical double layer at interfaces. Professor Healy's companion studies on the nature of adsorbed water and his more recent electrochemical studies on zinc and other sulphides are an important contribution to our understanding of wettability and flotation. Although Professor Healy's studies have been carried out using a variety of adsorbents and adsorbates they have an impressive scientific unity; they also constitute a major contribution to the understanding of important industrial processes involving solid suspensions.