Christopher Earls Brennen is the Richard and Dorothy M. Hayman Professor of Mechanical Engineering Emeritus in the Faculty of Engineering and Applied Science at the California Institute of Technology. He has published more than 200 referred articles and is especially well known for his research on cavitation, turbomachinery, and multiphase flows. He is the author of three textbooks - Fundamentals of Multiphase Flows, Hydrodynamics of Pumps, and Cavitation and Bubble Dynamics - and has edited several others. Among his many honors and positions are UN Consultant to India (1980); NASA New Technology Award (1980); ASME Centennial Medallion (1980); Chair ASME Fluids Engineering Division (1984–5); ASME R. T. Knapp Award for Best Paper (1978 and 1981); Caltech Student Award for teaching excellence (1982, 1995, 1996); Christensen Fellow, St Catherine's College, Oxford (1992); Fellow of the Japan Society for Promotion of Science (1993); JSME Fluids Engineering Award (2002); and Vice-President of Student Affairs at Caltech.