Neal Stephenson is one of the most popular writers of speculative fiction in the world. His novels Snow Crash and the Hugo-winning The Diamond Age redefined cyberpunk during the 1990s. His sequence of historical fabulations published under the collective title “The Baroque Cycle” were best-sellers. His latest novel is REAMDE. Master of techno-history.
Labels such as science fiction are most useful when employed for marketing purposes, i.e., to help readers find books that they are likely to enjoy reading. With that in mind, I’d say that people who know and love science fiction will recognize these books as coming out of that tradition. So the science fiction label is useful for them as a marketing term. However, non-S.F. readers are also reading and enjoying these books, and I seem to have a new crop of readers who aren’t even aware that I am known as an S.F. writer. So it would be an error to be too strict or literal-minded about application of the science fiction label.