Professor Michael Ghil is a founder of theoretical climate dynamics and of advanced data assimilation. He has applied systematically dynamical systems theory to atmospheric and oceanic flows and to the whole-Earth system. His studies of climate variability on many time scales have used a full hierarchy of models, from the simplest ‘toy’ models all the way to Earth system models. Recently, he has contributed to data analysis and modeling in macroeconomics, population dynamics, and coupled climate-economy-biosphere modeling. Ghil has authored or edited a dozen books and co-authored over 350 papers in a variety of fields. He played a key role in national and international projects, is a member of several national academies, and has garnered a few top-level honors. He is currently Professor (emeritus) at the Ecole Normale Supérieure in Paris (France), Research Professor at the University of California at Los Angeles, Los Angeles (USA), and Visiting Professor at Imperial College London, London (United Kingdom).