Desires matter. What are desires? Many believe that desire is a motivational state: desiring is being disposed to act. This conception aligns with the functionalist approach to desire and the standard account of desire's role in explaining action. According to a second influential approach, however, desire is first and foremost an evaluation: desiring is representing something as good. After all, we seem to desire things under the guise of the good. Which understanding of desire is more accurate? Is the guise of the good even right to assume? Should we adopt an alternative picture that emphasizes desire's deontic nature? What do neuroscientific studies suggest? Essays in the first section of the volume are devoted to these questio...