Asimov's two big universes, found in the Robots series and the Foundation series, (which turned out to be the same when he revisited them in the 70's and 80's) are simply wonderful. By far my favorite sci-fi, and among the most enduring works in the genre. I read them both every two or three years, and sometimes grab one off the shelf when I just want something to read. The early Foundation is sort of a future history version of "The Decline and Fall of the Roman Empire" (I seem to recall that was intentional, actually). Asimov's autobiographies and the posthumous book of his correspondence are all fantastic and insightful. I learned a lot from them, and my admiration for the man increased even more upon reading them. Dune is also astoundingly good, though after the first three, the quality goes downhill (slowly, but surely). Definitely lots to think about.…
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