GEORGE GAYLORD SIMPSON'S passing in 1984 brought an era in vertebrate paleontology to an end. Along with Edward Drinker Cope, Henry Fairfield Osborn, and Alfred Sherwood Romer, Simpson ranks among the great paleontologists of our time. The intellects of several generations of students were shaped by either following or rejecting his elegant analyses and interpretations of evolution and the history of life.
Although the ''Simpson Era" had its roots in the 1920s and 1930s, it seemed to emerge fully formed and without precedent with the publication of Tempo and Mode in Evolution (delayed until 1944 by World War II), following belatedly on the heels of Quantitative Zoology (1939), which Simpson had written with Anne Roe. Both books left researchers in a variety of fields pondering and often revising, conceptual bases
Although I had earlier written a memorial to George Gaylord Simpson for the Geological Society of America, I agreed to prepare a more intimate and more personal essay for the National Academy of Sciences Biographical Memoirs. The more objective accounts of his life include the essay mentioned above (Memorial Series, Geological Society of America, 1985) and the essay by Bobb Schaeffer and Malcolm McKenna (News Bulletin, Society of Vertebrate Paleontology, no. 1933, 1985). Simpson's autobiography, Concession to the Improbable (New Haven: Yale University Press, 1978) and his book, This View of Life: The world of an evolutionist (New York: Harcourt, Brace and Company, 1964) provide a more comprehensive view of his life and thoughts.