The Lamont-Doherty Earth Observatory (LDEO) celebrated its fiftieth anniversary in 1999. As part of" the effort to preserve the history of this important earth science research institute, senior Lamont administrators conceived an ambitious oral history project. Now complete, these oral histories present a useful resource for those studying the history of the earth sciences, environmental history, social and institutional history, disciplinary development, technological change, internationalism in the sciences, and patronage. This article summarizes certain preliminary conclusions reached during the course of this project.