Ugo Bastolla is researcher in the laboratory of bioinformatics of the Centro de Astrobiologia in Madrid (Spain), on leave to the Centro de Biologia Molecular of the Spanish CSIC. Since his degree in physics with Luca Peliti he has always been interested in biological topics, above all evolution. He got is PhD in Rome with Giorgio Parisi working on disordered dynamical systems inspired to biology and was postdoc in Julich (Germany) with Peter Grassberger, studying statistical mechanical models of polymers, in Berlin (Germany) with E.W. Knapp studying simple protein models, in Golm (Germany) with Michael Laessig, studying ecological models, and finally in Madrid (Spain) in the bioinformatics group of Alfonso Valencia. His main research interest consists in combining simple models of protein thermodynamics and evolution. Markus Porto is professor of Theoretical Solid State Physics at the Institut fur Festkorperphysik at the Technische Universitat Darmstadt (Germany). He received his PhD at the Universitat Giessen (Germany). His research interests cover many aspects of solid state and statistical physics, including transport and relaxation in disordered systems and biophysics, as well as applying methods of statistical physics to model molecular evolution. H. Eduardo Roman is Research Fellow at the Department of Physics of the University of Milan-Bicocca. He earned his Ph.D at the International School for Advanced Studies, Trieste (Italy), and has been Privat Dozent at the Universities of Hamburg and Giessen (Germany). His research interests cover many aspects of Statistical Physics, from fractals to stochastic phenomena, biophysics, proteins and evolution, and ab-initio electronic calculations in molecules. Michele Vendruscolo is a Royal Society University Research Fellow at the Department of Chemistry, University of Cambridge. He received his PhD in Condensed Matter Physics in 1996 at the International School for Advanced Studies, Trieste (Italy). His research is mainly focussed on understanding the biophysical principles regulating the behaviour and the evolution of proteins.