"The Seedling Stars" by James Blish is a relatively short book, but, interesting for those who are appreciative of Sci-Fi. Actually a group of short, related stories, it tells of a ship of genetic scientists who traverse the galaxy "seeding" various planets with genetically-adapted life forms who possess human intelligence, beginning "human" evolution on worlds that would not support "regular" human life as we know it. The several stories relate the experiences of several individual "humans" (in their new forms) on these worlds, as they discover their humanity and take steps to advance their uninformed and supersticious cultures and their search to understand where they came from and the nature of their existences. One world is a place of tree-dwelling primate-people, another, a water-world of microscopic aquatic humans (generated for that world by the scientists in a last-ditch effort to expand humanity onto that world after their ship crashes on it.). This was a very enjoyable book with a concept that really makes you wonder about our origins (in a sci-fi sort of way), and inspires you to contemplate "what if...".