Robert Jastrow is well known internationally as an astronomer and author of many widely acclaimed books. His initial research experience was in the field of nuclear physics, and his later work has been in planetary science, atmospheric physics, weather and climate prediction, and application of satellite observations to studies of earth resources. Dr Jastrow joined NASA when it was formed in 1958 and in 1961 set up NASA's Goddard Institute for Space Studies, a U.S. Government laboratory charged with carrying out research in astronomy and planetary science. Michael Rampino is an associate professor of earth science and biology at New York University, and a research associate at GISS in New York. His research spans many areas of the earth sciences, especially the inter-relationships between the Earth's changing environments and the evolution of life. He is Series Co-Editor for the highly acclaimed Encyclopedia of Earth Sciences (Springer) and the Editor-in-Chief of the Earth Science Encyclopedia On-Line.