The riddle of the future bewilders human beings. On the one hand, we are inclined to think that future events are real in some sense, because we ask questions and make assertions about them. On the other hand, we are inclined to think that future events may depend on our choices, because we conceive of ourselves as free agents. These two inclinations seem to clash. If an event belongs to the future, then it is a fact that it will occur, and we cannot prevent it from occurring. Inversely, if we can prevent an event from occurring, then it cannot be a fact that it will occur. This apparent conflict is at the core of the debate on future contingents, a philosophical dispute that goes back to antiquity. Future contingents are sentences that concern future events that can occur or not occur. The question that started the debate—whether future contingents are true or false—is a question that has no clear answer, given that one may have different views about the truth and falsity of a sentence about the future. Yet an answer must be provided, and it cannot be just any answer. The constraints that define the problem of future contingents determine a restricted set of admissible answers, each of which gives rise to doubts, troubles, and complications.