Antonio Cabrales is Full Professor of Economics at Universidad Carlos III, Madrid, Spain. He has previously been a professor at University College London and at Universitat Pompeu Fabra. He is Executive Vice President of the European Economic Association, Fellow of the Econometric Society, and former President of the Spanish Economic Association. He has worked in a wide range of topics including game theory, the economics of networks, mechanism design, economics of education, experimental and behavioural economics. Ismael Sanz is an Associate Professor in the Department of Applied Economics at King Juan Carlos University, Madrid, Spain, and a Visiting Senior Fellow at the LSE. He has served as Chair of the Strategic Development Group of PISA at the OECD. His research has been widely published in economics journals, including Economic Journal, Oxford Bulletin of Economics and Statistics, Scandinavian Journal of Economics, and Canadian Journal of Economics.