a number of fallacies: naturalistic fallacy: Mill is trying to deduce what people ought to do from what they in fact do; equivocation fallacy: Mill moves from the fact that (1) something is desirable, i.e. is capable of being desired, to the claim that (2) it is desirable, i.e. that it ought to be desired; and the fallacy of composition: the fact that people desire their own happiness does not imply that the aggregate of all persons will desire the general happiness. Such allegations began to emerge in Mill's lifetime, shortly after the publication of Utilitarianism, and persisted for well over a century, though the tide has been turning in recent discussions. Nonetheless, a defence of Mill against all three charges, with a chapter devoted to each, can be found in Necip Fikri Alican's Mill's Principle of Utility: A Defense of John Stuart Mill's Notorious Proof (1994). This is the first, and remains the only, book-length treatment of the subject matter. Yet the alleged fallacies in the proof continue to attract scholarly attention in journal articles and book chapters. Hall (1949) and Popkin (1950) defend Mill against this accusation pointing out that he begins Chapter Four by asserting that "questions of ultimate ends do not admit of proof, in the ordinary acceptation of the term" and that this is "common to all first principles". Therefore, according to Hall and Popkin, Mill does not attempt to "establish that what people do desire is desirable but merely attempts to make the principles acceptable." The type of "proof" Mill is offering "consists only of some considerations which, Mill thought, might induce an honest and reasonable man to accept utilitarianism." Having claimed that people do, in fact, desire happiness, Mill now has to show that it is the only thing they desire. Mill anticipates the objection that people desire other things such as virtue. He argues that whilst people might start desiring virtue as a means to happiness, eventually, it becomes part of someone's happiness and is then desired as an end in itself. Henry Sidgwick Sidgwick's book The Methods of Ethics has been referred to as the peak or culmination of classical utilitarianism. His main goal in this book is to ground utilitarianism in the principles of common-sense morality and thereby dispense with the doubts of his predecessors that these two are at odds with each other. For Sidgwick, ethics is about which