 This theological fatalist argument creates a dilemma for anyone who thinks it important to maintain both (1) there is a deity who infallibly knows the entire future, and (2) human beings have free will in the strong sense usually called libertarian. But it has also fascinated many who have not shared either of these commitments, because taking the argument’s full measure requires rethinking some of the most fundamental questions in philosophy, especially ones concerning time, truth, and modality. Those philosophers who think there is a way to consistently maintain both (1) and (2) are called compatibilists about infallible foreknowledge and human free will. Compatibilists must either identify a false premise in the argument for theological fatalism or show that the conclusion does not follow from the premises. Incompatibilists accept the incompatibility of infallible foreknowledge and human free will and deny either infallible foreknowledge or free will in the sense targeted by the argument.