This chapter presents two contrasting pictures of the will. On the first, “the will” is a psychological structure or module within a person that originates spontaneous or endogenous activity, independently of external influence. On the second, “the will” is that collection of ordinary states of mind (cares, concerns, beliefs, desires, commitments, fears, etc.) that generates intentional, voluntary, or responsible activity—it is the functioning together of those aspects of mind that account for human activity. A challenge is posed for each. The challenge for the first is to say how the outputs of this module are the activity of the person. The challenge for the second is to say how psychological activity that might be entirely explained by a person’s history and environment can nonetheless be free and responsible activity. The replies take up an important question about the role of consciousness in each picture.