We have two ways of talking about liberty or freedom, one in the singular, the other in the plural. We concern ourselves in the singular mode with how far someone is free to do or not to do certain things, or with how far someone is a free person or not a free person. But, equally, we concern ourselves with the plural question as to how far the person enjoys the liberties that we take to be important or basic. What are those plural liberties, however? What does it take for something to count as a basic liberty? e usual approach to this question is to give a list of some presumptive basic liberties — say, those of thought, speech, and association — and then to add a gestural ‘and so on’. My aim in this paper is to do a little better in elaborating a conception of the sorts of liberties at which the ‘and so on’ gestures. I argue that the basic liberties can be usefully identifi ed as the liberties required for living the life of a free person or citizen and I spell out that requirement in three constraints, which I describe as feasible extension, personal signifi cance and equal co-enjoyment. ere are many candidate sets of basic liberties that might be proposed for protection, whether in general or for a particular society. e claim that I defend is that in order to count as a set of basic liberties, the types of choice protected under any proposal should be capable of being equally enjoyed at the same time by everyone (equal co-enj oyment), should be important in the life of normal human beings (personal signifi cance), and should not be unnecessarily restricted: they should be as extensive as the other constraints allow (feasible extension). e aim of the paper being quite limited, I abstract from many important issues. I do not provide an argument for why it is important that some set of basic liberties be protected, nor do I rate the importance of such protection against other social goals. I say nothing on how far it should be a requirement of democracy that certain sorts of liberties are entrenched—whether constitutionally or otherwise—and how far democratic process should be allowed to vary the specifi - cation and protection of basic liberties...