Giuseppe Bertin is Professor of Physics at the University of Milan, Italy. He has previously held several positions at the Scuola Normale Superiore and the Massachusetts Institute of Technology, and has been a member of the Kavli Institute for Theoretical Physics, University of California, Santa Barbara. His previous books include Spiral Structure in Galaxies: A Density Wave Theory with C. C. Lin (MIT Press) and Dynamics of Galaxies (Cambridge University Press). He was elected to Italy's Accademia Nazionale dei Lincei in 2013, when he received its Premio Nazionale del Presidente della Repubblica in Science.