The distinguished contributors are: S Adler, P van Baal, F A Bais, C Becchi, M Creutz, A DeRujula, B S DeWitt, F Englert, L D Faddeev, P Hasenfratz, R Jackiw, P van Nieuwenhuizen, A Polyakov, R Stora, S Weinberg, F Wilczek, E Witten, C N Yang. Included in each article are introductory and explanatory remarks by the editor, G 't Hooft, who is himself a major player in the development of Yang-Mills theory.