AB E -- the quote isn't found on twainquotes.com and best I can tell, did not originate with Mark Twain. It has taken on a life of its own with attribution to Mark Twain. However, searching google for the quote with attribution to someone else besides Twain using these search terms: "poor fight back" + violence -twain yields over 84,000 results. The true source of that quote might be buried there somewhere. It appears to be another case of "if it sounds good, Mark Twain must have said it." Barb