Gene Rasmusson's research career began in earnest while he was a graduate student at MIT from 1963-1966 as a member of the research group directed by Victor Starr. His PhD thesis on the atmospheric branch of the hydrologic cycle over North America represented a major departure from the mainstream research on Starr's project in the sense that it was regional in focus and it dealt with a range of issues that had heretofore been regarded as largely hypothetical. Published in 1971, this pioneering study presaged contemporary field programs such as GEWEX. During the first decade of his career, Rasmusson's devoted considerable effort to the analysis of data from the Barbados Oceanographic and Meterological Experiment (BOMEX). He showed how radiosonde data from just a few sites could be used to constrain and provide a large-scale context for estimates of the vertical profiles fluxes of sensible heat and water vapor. Rasmusson's most widely cited work can be traced back to the late 1970's when he became interested in the Comprehensive Ocean Atmosphere Data Set (COADS) that was under development in NOAA. In his preliminary analysis of COADS he recognized and documented the recurrent signature of warm episodes that encompassed not only the coast of South America, but also the entire equatorial Pacific cold tongue region extending to the date line. The Rasmusson and Carpenter study of ENSO, based on this work and published in 1982, is one of the cornerstones of our current understanding of ENSO.