Anthony Horsley (1939--2006) was a British mathematical economist and a nuclear physicist who in the 1960s worked for the U.K. Atomic Energy Authority (becoming then its youngest ever Senior Scientific Officer) and for the Council for Scientific Policy. Later, devoting himself to academic research and teaching, he worked on the theory and applications of competitive equilibrium at the University of Sussex, Oxford University and, from 1979 until retirement and untimely death, the London School of Economics. A Renaissance mind, he also had a keen interest in literature, history and politics. He received a Ph. D. in Mathematical Physics from the University of Birmingham and a D. Phil. in Economics from the University of Oxford. Andrew J. Wrobel (b. 1955) is a Polish-born mathematical economist. He has worked at the Institute of Computer Science in Warsaw and, as a Senior Research Fellow, at the London School of Economics and the Catholic University of Brabant in Tilburg. His main research, joint with Anthony Horsley, is on the theory of competitive equilibrium and its applications to the electricity supply industry. Educated in Warsaw, and in Bonn and London on postgraduate grants from the Studienstiftung des deutschen Volkes and the LSE, he holds an M.A. in Mathematics from the University of Warsaw and a Ph.D. in Economics from the University of London.