The libel suit between Penguin books and David Irving, the controversial second world war historian, over his version of the Holocaust, began on Tuesday in the High Court in London. “The case raises a number of questions: When are the ideas of historians or academics so appalling that their work should be forever banned from public consumption? What limits do you place on free speech? And what makes a good historian anyway, especially when their subject is that most emotive one in 20th century history?” –Financial Times