I randomly stumbled on the Proxima & Ultima duology by Stephen Baxter and they shot up to the top echelon of my favorite books list. Near-future sci-fi, interstellar travel, alternate histories, alien cultures, non-human cognition. Just wonderful stuff to randomly pick off the library shelf because they had a cool sounding name. I actually read the 2nd book first by accident, and thought it worked pretty well in retrospect. I also liked Eon by Greg Bear (RIP), for actually quite similar reasons.
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