Utilitarianism is Mill's most direct attempt to refine his inherited doctrine. Even more concise than On Liberty, this also essentially picks up where it left off, delving into the practical problem of how to deal with conflicting liberties. Mill retains the core utilitarian tenet that what brings the most happiness for the most people should be acted on - a very appealing doctrine in itself and put forth more palatably and persuasively than by the prior generation. However, utilitarianism's many critics will find little to convince them; however ideally attractive, many practical problems arise when issues such as relative happiness and harm turn up, as well as the thorny problem of how to enforce utilitarianism and punish transgressions. Mill makes some headway, covering nearly all conceivable ground in general principles but leaving much practical application unaddressed. It may be the most spirited utilitarianism defense ever but unfortunately is not complete, however admirable in many ways. That said, it is essential for anyone interested in Mill or utilitarianism.