A few questions from a newcomer to the genre

[Penfeather]

I have another question:
Are any of the authors known witches?
I hope this is not a ridiculous question, as I read on the front of a book (I don't know what it's called, but when praise is given to an author by a publisher or another author, etc.) something about the author being a witch. It seems like it was Charlotte Armstrong.

I tried reading one Charlotte Armstrong book (I believe it was called The Witch's House) and gave up halfway through. It had been mis-marketed as a Gothic, and this wouldn't necessarily be a problem, but I simply didn't care for the book.

If you're seeking to avoid depictions of witchcraft or that sort of thing in your reading, I should warn you that Winter Castle, the book you were seeking to identify, does contain some elements of black magic in its plot, if memory serves me. I remember thinking that it was a good story marred by some absurd/contrived sequences.