io9 makes a good point: Many lists of books that claim to be “hard” SF–in the sense of being rigorously scientific–either include works that are only hard if you squint (like Dune, where you’ve got people folding space with their minds) or don’t explore new technologies. As they put it, “It’s as if most definitions of hard SF were written back in the 1950s and not rethought much since.”
They’ve put together a list of ten books that they feel are transforming hard science fiction and moving it in new directions. It’s somewhat eclectic, but sounds interesting.