Sidgwick and the Methods of Ethics
Henry Sidgwick (1838–1900), Knightbridge Professor of Moral Philosophy at Cambridge from 1883, published The Methods of Ethics in 1874, revising it through six further editions during his lifetime, the seventh and final edition appearing in 1907 shortly after his death. The book is widely regarded as the most rigorous and philosophically exhaustive treatment of utilitarianism ever produced: John Rawls, in A Theory of Justice (1971), called it the outstanding and most carefully worked out account of the utilitarian tradition available, and Derek Parfit, in On What Matters (2011), devoted extended discussion to reconstructing and extending its arguments, treating Sidgwick as one of the small handful of truly indispensable moral philosophers.
Why do you think there's historiographical debate about "Sidgwick and the Methods of Ethics"?