In Anarchy, State, and Utopia, how does Nozick think we should think about rights?
Nozick famously describes what we would think of as "right" in terms of "side-constraints." These are things that either the state or the individual cannot do, in short, because they harm others. Novick includes many actions of government, like taxation, in his formulation, essentially arguing that the social contract ought to exist at a level below the state. Government's only purpose is to ensure the efficacy of these constraints, which it must always do with an eye to preserving them. This is different from those who make the preservation of rights, or, as John Rawls argued, the establishment of justice, the end of society. As Novick puts it:
The side-constraint view forbids you to violate these moral constraints in the pursuit of your goals; whereas the view whose view is to minimize the violation of these rights allows you to violate these rights (the constraints) in order to lessen their total violation in the society.
Novick's view is a radical form of libertarianism, one which severely limits the theoretical extent to which an individual lives in society. It should be read in part as a refutation of the theory of justice posited by John Rawls (Novick's Harvard colleague) in his book A Theory of Justice.