In this interview, Klaus Hasselmann discusses topics such as: his family background and how he became interested in physics; getting his PhD from the Max Planck Institute for Fluid Dynamics and Gottingen University; Walter Tollmien; University of California, San Diego Institute for Geophysics and Planetary Physics; Scripps Institute of Oceanography; Walter Munk; Norman Barber; John Miles; Hugh Bradner; George Backus; Klaus Wyrtki; Carl Eckart; Charles David Keeling; researching storms in the south pacific including Hawaii; Frank Snodgrass; Gordon Groves; measuring waves in the North Sea; becoming director of the newly formed Department of Theoretical Geophysics at the University of Hamburg; Donald Menzel; the Max Planck Institute for Meteorology; North Atlantic Treaty Organization (NATO); Woods Hole Oceanographic Institution; Wolfgang Sell; Art Maxwell; Dirk Olbers; Heinz-Hermann Essen; Peter Muller; wave dynamics; Global Atmospheric Research Programme (GARP); Reimar Lust; Kirk Bryan; World Climate Research Programme; European Centre for Medium Range Weather Forecasts (ECMWF); Lennart Bengtsson; El Nino predictions; Intergovernmental Panel on Climate Change (IPCC); carbon dioxide emissions; Hans Hinzpeter; plasma physics; quantum field theory.