Addictions and compulsions pose, most centrally, the question of how we ought to understand our actions when they are, by common understanding, not entirely free. On the one hand, are the compelled and addicts forced to act? If so, do they force themselves, or are they forced by their psychology, or by their neurobiology? Each of these possible explanations are problematic. How do we force ourselves? Why is part of our psychology independent of "us"? What relationship is there between neurological explanations and psychological explanations? On the other hand, if the compelled and addicts are not forced to act, what accounts for their consistently bad and even self-defeating actions and for their regularly violating their own resolutions to change their actions? Such attempts to explain addiction and compulsion also shed light on ordinary actions and action explanations and on what it means for actions to be free.