This book is largely focused on the issue of responsibility; its chapters discuss topics all significantly related to this issue, including metaphysics, action theory, ethics and moral theory, and the philosophy of law. One of the main topics in this chapter is the metaphysics of moral responsibility, in which two relevant conditions are necessary in order for a person to assume responsibility for an action. First, there is a freedom-relevant condition and, second, there is an epistemic condition. The former has always been controversial such that there exists no generally accepted view of its principles; the few uncontroversial ones will be the subject of discussion here. The “alternatives view” of free will, which states that an action is free only if the doer had alternative possibilities of action, is also examined here.