Damien Challet graduated as a physicist at the Swiss Institute of Technology, Lausanne, and obtained his Ph.D at Fribourg University under the supervision of Prof Yi-Cheng Zhang. He then spent three years as a postdoctoral fellow in Theoretical Physics at Oxford and is now Nomura Junior Research Fellow in Financial Mathematics, Oxford, jointly with Wadham College. He was given the Young European Scientist Award in Socio- and Econophysics in 2002. Matteo Marsili graduated in physics at La Sapienza in Rome. Then he moved to Trieste, obtaining his Ph.D. at SISSA in 1994. Having been a researcher at the Istituto Nazionale per la Fisica della Materia in Trieste, he is now Research Scientist at the Abus Salam International Centre for Theoretical Physics. Yi-Cheng Zhang obtained his Ph.D on particle physics in 1984 under Giorgio Parisi in Rome and then completed a two-year postdoctoral stint at Brookhaven National Lab USA (1984-1986). He was a senior researcher at Istituto Nazionale Fisica Nucleare (1986-1991). Since 1992, he has been Professor of Theoretical Physics at Fribourg University in Switzerland.