Jem

Simply a remarkable book, even better than Gateway and probably one of the top 10 scifi books I have ever read (as of March 2012). The contributions are both anthropological and political. I also always enjoy Pohl's futurology settings, taking place at the beginning of the interesting part of the Space Age. Also, the main character is very accessible, a lot like other space inclined people without a real valuable trait that would earn them a spot in space. There is so much more...
Will be reading the rest of his work soon.