Carl Sagan may be one of the best-known scientists of the last half of the 20th Century. His book, Cosmos, which was made into an immensely popular television series, has been instrumental in spreading an awareness and enthusiasm for astronomy on a par with the interest in science fantasy generated by the film "Star Wars." As a tireless proselytizer for science, Sagan succeeds in making his passion highly appealing while also presenting it in language understandable by the reader with only a slight formal background in science who is ready to share in the excitement the astronomer purveys.