Millennium

Another story about things gone bad in the future (the story's present). A gazillion nuclear wars, general pollutions and what-have-you, and the human gene-pool doesn't look too good by now.  The civilization that calls itself 'The Last Age' (sounds like it!) decide to solve the problem by getting some fresh blood (sorry, that should be 'genes') by getting some humans from a past where the gene pool was still kind-of OK and regenerating the species on the space equivalent of some quarantine island. Like the folks in #7 they are trying to make sure that they collect only those who are about to die anyway. Of course, the 'Snatch Teams' are noticed and that means there are repercussions reverberating into the future 'now'. (Butterflies again.) In fact, during one raid a weapon was left behind that must be recovered at all costs if a serious paradox is to be avoided. Why it's on the list: Good story, solidly told and sticking with the program. The trick with all these tales is not to become too complicated, but also to stay as real as you can get, based on the assumptions you start with. With anything having to do with time, that's never easy.