I can remember reading this when I was quite young, and then seeing the 48' film version of it, and at some point between reading about how menacing Bill Sikes was and then seeing him beat his girlfriend to death with a cane in the film (well, yes, it was obscured by a wall, but you knew what was happening) I became intrigued by his character. I was way too young too understand all the themes of the book, and I can't remember the things I'd like to, and that particular scene horrified me when I read it and watched it; but I do know I find alot about Bill to muse over.
For one, whether he was really in love with Nancy; whether he did really feel an attachment to Bull's Eye; I suppose, the whole question of whether he was mentally, and emotionally, "rotten" to the core. I personally have always felt that, whilst his opinion and view and version of love is not the sort the majority would share with him or understand, Bill does indeed love Nancy and Bulls Eye in his own (highly) dsyfunctional way. Lots of people have argued with me on this, with a few people I know claiming that Bill's "only working emotion is hate"; but I feel there's a small spark of compassion and empathy in there somewhere, something that makes him realise he has an attachment to Nancy and his dog that goes beyond a mutually beneficial partnership. Maybe it isn't something he dwells on too much, or likes to think he has, but I think he has that; which, to him, is love.
My first musing leads neatly into my second-what balance was there between his innate nature and his nurturing as he grew up that drove him to the person he was when we see him in the book and film? Was he naturally quite hardened emotionally as part as his genetical inheritance, and his (presumably) tough upbringing just enhanced this; or was he born pretty much neutral in terms of violence and indifference, and it was mostly his upbringing that instilled in him such anger and such hatred? Obviously, I'd never be naive enough to ask which one it was that produced such a man-you cannot ever say that it was either someone's innate nature or their nurture that made them turn out a certain way, but you can debate over which one played the bigger part, which one swung the balance.
Also, as a sort of add-along, I cannot remember the book saying anything particular about Bill's childhood and upbringing before Fagin; is that true? I pressume he had an early life of hardship, born to parents that didn't want him or couldn't look after him; or both, or maybe he became orphaned early on-or maybe, his parents didn't want him and couldn't look after him, and then he also orphaned early on. When we discussed Dickens in one of my recent English classes, my teacher criticised me for suggesting that he had abusive parents, or was neglected by them, or both; yet I can't see why she did. I think she was just a bit unnerved at how I saw past the whole "happy bouncy musical" side of the book.