This article provides an understanding and defence of 'best interests'. The analysis is performed in the context of, and is informed by, English law. The understanding that develops allows for differences in values, and is thus argued to be appropriate in a pluralist liberal system. When understood properly, it is argued, best interests provides the best means of decision-making for people deemed incompetent to decide for themselves. It is accepted that some commentators are cynical of best interests in practice. Following an assessment of some of their principal concerns, it is suggested that best interests in fact provides a construct that is both defensible and desirable.