A slightly revised version of a talk given at Cornell University, November 13, 1981. A tape recording of the session, including the question and answer period following, is available as an mp3 from the IBRI website: www.ibri.org. Sagan's Cosmos is characterized as evangelism for secular humanism. His treatment of Christianity is examined. Weaknesses in his oscillating big-bang cosmology are noted, as well as problems faced by a naturalistic view of the origin of life. Evidence is given which allows us to make a rational choice between secular humanism and Christianity.