So changes were made for the series, which debuts Sunday on Syfy. But they were devised mostly without Martin’s input because of his exclusive deal with HBO. He was able to share a few thoughts, though, including about an old casting decision he’s always regretted.

In a phone interview, Martin discussed this, future “sexing” and how the largely unloved “Nightflyers” movie saved his career. He also shared a few details about his “Game of Thrones” successor series, which he still refers to as “The Long Night” even though HBO told him not to. These are edited excerpts from the conversation.

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The character Melantha Jhirl is a black woman in the novella, but on one of the book covers and in the 1987 movie adaptation, she was white. How did you feel about that whitewashing then and about the new show’s casting of the black actress Jodie Turner-Smith?

Just having her cast was very gratifying to me after what happened in the 1980s. I wrote the lead character as a black woman — in fact, the name Melantha means “black flower.” And initially, when the story was first published in a magazine, Analog, they put an astronomical cover on it, just the spaceship. But a couple of years later it was reprinted in a short story collection, and that was the first one to show a character on the cover. And to my surprise and shock, the character was a white woman! I phoned up the editor and I said: “This is wrong. She’s explicitly described as being black.” And they said: “Yeah, we know that. But you want your book to sell, don’t you?” “Well, yes, I would like my book to sell.” “Well, if we put a black woman on it, it won’t sell.” To my shame and regret ever since, I caved. And then, when it was made into the movie, they cast a white actress in the role. I don’t know if that was for the same reasons.

But it’s always bothered me, and I’ve always thought I should have done more. Today I’m more famous and more powerful but then, I was just one writer among many struggling to make a living. So when I learned that they were making a TV series, that was the one thing I came in on: “Let’s cast a black actress.” And we were all on the same page, and we finally got it right. And Jodie Turner-Smith is marvelous in the role.