Many references to Twain's opposition to slavery in any form can be found throughout his work. You might want to look at the entry under "Slavery" in the Mark Twain Encyclopedia edited by Jim Wilson. Turn to the Autobiography of Twain arranged & edited by Neider, not a favorite of scholars for textual reason s, but handy enough to extract the kind of stuff you're looking for. LOOK AT the end of Chapter 3. And this from Chapter 8: As I have said, we lived in a slaveholding community;indeed when slavery perished, my mother had been in daily touch with it for sixty years. Yet, kind-hearted and compassionate as she was, I think she was not conscious that slavery was a bald, grotesque, and unwarrantable usurpation. That's a beginning. Look at other works by and about Twain and try using the index to extract some indications of the full range of his loathing of the practice. ACR