  Questions about the existence and nature of mental causation are prominent in contemporary discussions of the mind and human agency. Originally, the problem of mental causation was that of understanding how an immaterial mind, a soul, could interact with the body. Most philosophers nowadays repudiate souls, but the problem of mental causation has not gone away. Instead, focus has shifted to mental properties. How could mental properties be causally relevant to bodily behavior? How could something mental be a cause qua mental? After looking at the  traditional Problem of Interaction, we survey several versions of the property-based problem along with potential solutions. 