Professor Preston Cloud (1912-Jl990) (Preston Cloud, a great name in Earth Science is no more, His was a versatile mind which probed into many aspects of Earth history. We pro­ duce below a short life history of the famous professor written specially for the Journal by Somadev Bhattacharji, Professor of Geology, New York State University, Brooklyn, New York.-Ed. With the death of Professor Preston Cloud, Emeritus Professor of Geology at the Department of Geological Sciences, University of California, Santa Barbara~ the Earth Sciences have lost one of their most eminent spokesman. Professor Cloud was born in eastern Massachusetts in 1912. He started his undergraduate study of geology in a one-professor department at George Washing­ ton University at Washington, D.C. while holding a tenuous job in the Smith­ sonian Institution's Natural History Museum during the great depression yea'rs in the U.S.A. This early experience influenced his later career in geology. He graduated from George Washington University in 1938, and continued on to receive his Ph.D. from Yale University at New Haven, Connecticut in 1940. After a long association with the U.S. Geological Survey as a geologist and paleonto­ logist, he retired in 1979. He also taught at the Missouri School of Mines~ Harvard University, The University of Minnesota, and the University of California at both Los Angeles and Santa Barbara. In the last years of his active retired life, Santa Barbara was his base, but he travelled widely to see · real geology' and lectured and inspired many, beside being busy writing. Immediately after his retirement from the USGS, he served for a year each as H. R. Luce Professor of Cosmology at Mount Holyoke College, Massachusetts and as a Queen Elizabeth II Senior Fellow of the Department of Science at the Baas Becking Institute of Geobiology in Canberra, Australia. During his years at Santa Barbara he received many bonors, the highest among them being the PI!nrose Medal of the Geological Society of America, membership of the National Academy of Sciences, U.S.A., and the foreign membership in the Polish Academy of Sciences. Besides being an ardent spokesman for geological sciences, he is best known for his monumental work on biological processes in Earth History and biosphere/geosphere interactions during pre-Phanerozoic time. Among his many works on Earth History, a recent paperbaek Oasis in Space summarizes the way he looked at mother earth. In another short reminiscence about his experience in geology for the young geologists (Compass, 1989), be wrote: 'Geology during the half-century since my school days has undergone a couple of revolutions-not only the plate tectonics revolution, but a geochemical revolution (including geochronology), a marine science revolu­ tion, and a revolution in our knowledge of prc-Phanerozoic history. Geology remains the most interdisciplinary of sciences, only more so'. On specialists and generaJists in geology: ' ... a dedicated specialist may focus on some specific component or process for a life time, with profound and far~reaching results. Generalists reach for broader connections learning new fields and often switch fields in the process. Both are needed, but the best generalists start as specialists-where they gain the necessary depth, and the recognition that evidence take priority in all areas of scientific discourse. Objectivity may be beyond human grasp, but all scientists are obliged to strive for it.' For the geoscientists of today and tomorrow these are cautionary reminders. Preston Cloud-a visionary geologist, outstanding educator and a true scien­ tist, will be terribly missed. .