Giuseppe Grosso graduated in Physics at the University of Pisa in 1972 and PhD from the Scuola Normale Superiore in 1977, He is a retired full professor of Solid State Physics at the Physics Department of Pisa. The main research topics addressed concern electronic and optical properties of perfect 3D and nanostructured solids, Green's function, recursion and renormalization methods, continued fractions coherent transport, Keldysh formalism, conjugated polymers and molecular crystals, silicon and germanium based photonics.Giuseppe Pastori Parravicini graduated in Physics at the University of Milan in 1963, then moved to the Physics Institute of the University of Pisa where he taught Solid State Physics for more than two decades. From 1990 he moved as full professor to the Department of physics of the University of Pavia where he taught until 2011. Giuseppe Pastori Parravicini has made original contributions in many areas of theoretical Solid State Physics. Among them are the study of lamellar compounds, the theory of symmetries for the classification of electronic states, the electron-phonon interaction, nonlinear optical spectroscopy, many-body effects in excited states in atoms, molecules and solids, quantum transport using the non-equilibrium Keldysh function.