Dennis D. Klug is a Principal Research Scientist at the National Research Council of Canada in Ottawa, Canada. He graduated from the University of Wisconsin, Madison, US, with a Ph.D. in chemical physics in 1968 where he carried out research on statistical mechanical studies of polar liquids. This was followed by a post-doctoral appointment and staff scientist appointment in Ottawa where he carried out research in crystalline and amorphous solids under extreme conditions of high pressures and/or low temperatures. He has maintained a mixture of theory and experiment in his research program and his main current interests are in the areas of predictions and characterization of structures and properties of materials using tools varying from first-principles quantum methods to synchrotron radiation and neutron scattering techniques. In 2009 he was recognized as an Outstanding Referee by the American Physical Society.