Another book on evolution by a populist author not really for the serious Biology studen. nRead Origin of the species for the real thing Or the Beak of the Finch for good reseach into natural selection on the galapagos. Sagan once again falls down on his interminable belief that we can find life on other planets. On the good side this book brings to the layman the evolution story written in good prose however it repeats most of his previous excursions into this suject. We all have one book in us and this is Sagan repeat. Sad when he could have utilised his brain to research black smokers and chemobacteria to more effect