Dear Amy: I am a retired college professor who did years of research about American slavery and slaveholders. I own a set of very racist 19th-century books that were part of my research. It is now time for me to reduce the size of my library, but I am afraid to sell these books because, given the mood in our country today and the rise of white supremacy, I’m afraid these books will be bought by people who will be reinforced in their racist ideologies. I know they can get the books in other ways (if they knew about them), and I don’t believe in burning books.