Dr C. J. Ash has made notable discoveries in each of three separate areas of pure mathematics, namely universal algebra, semigroups and logic. His work is characterized by deep insight and technical virtuosity, leading to elegant and powerful solutions of central key problems which had previously been attacked, with only partial success, by many workers throughout the world. As a result his published papers are invariably of permanent importance and stimulate extensive further research and are greeted with great praise and enthusiasm.