Never met any of those sf stars (haw!), but Asimov's wife Janet Jeppson was a frequent visitor at B&N Lincoln Triangle. (Lived right down the block.) She was amused that I addressed her as "Dr. Asimov." "My husband was 'Dr. Asimov', Michael." And I replied, "Well, you're an MD, so you're Dr. Asimov too!" And she was kind enough to give me an inscribed copy of one of her own novels. That's class!