Noted American astronomer and author (1934–1996) who became an international celebrity as writer and host of the landmark 1980 television series Cosmos. His novel Contact served as the basis for the well-received 1997 film of the same name starring Jodie Foster. TLS, one page, 8.5 x 11, Cornell University letterhead, May 24, 1978. Sagan writes to William Hartel in response to a request for guidance in embarking on a career in exobiology. In part: “I think I should first reiterate that no one has yet found life on other planets and therefore the subject is necessarily a speculative one. At the same time there are certain areas of the subject, such as the design of instrumentation for detecting life elsewhere or the investigation of organic matter on the moon or meteorites or interstellar space…. One person might be interested in the detection or possible radio signals from civilization on planets of other stars…. In general, preparation for exobiology should begin with a very strong background in mathematics, physics, chemistry, and biology….” In very fine condition. R&R COA.