The Templeton Gate - Authors - Poul Anderson

His scientific literacy is probably exceeded in the genre by only Asimov and Clarke, whereas the traditions of his ancestral heritage embues much of his work with a profound humanistic and libertarian philosophy, reminiscent of the best of vintage Heinlein. I would rank him higher in the SF heirarchy if not for what I consider his one shortcoming; the inability to create (with just a couple of exceptions) well-rounded, distinctively identifiable and believable characters. Even with that, I would still have to say that his galaxy-spanning narratives and hard-SF scenarios never overlook or overshadow the personal and emotional impact on his protagonists.