Abstract Abstract The argument of Part II so far has been that no account of free will can succeed, not even the compatibilist account of Part I. But there are, no doubt, readers who believe that libertarianism, or maybe libertarianism supplemented with some rationality constraints, can vindicate the notion of free will. So, it is to libertarianism that I turn directly. In this chapter, I argue that a libertarian conception of free will must satisfy the three conditions of the ability-to-choose-otherwise, control, and rationality, interpreted as dual abilities. I then look at two broad classes of libertarian theories, Nonvalerian theories that satisfy the first condition at the expense of the other two, and Valerian theories, none of which does better than compatibilist theories at satisfying the dual abilities. My conclusion is that the deep reason why no libertarian view can satisfy all three conditions is that the conditions are logically incompatible. Hence, libertarianism, despite its intuitive appeal, turns out to be incoherent, although it captures enough of the way we feel about freedom to rule out compatibilism. I conclude by suggesting that libertarianism has no resources of its own for dealing with rationality objections and must help itself to something like the compatibilist’s account from Part I, which we have already seen reason to reject.